Years ago before my wife and I were married and had kids we used to have a very special tradition on my birthday.  We moved in together about a year after we met.  I was finishing grad school and she was doing an internship.  We were broke.  So, like all good girlfriends she gave me a card with a bunch of "Get 1 Free ..." cards.  Each good for some sexual act.  I told her this was really great, but I'd give them all up if she'd spend the entire day in our apartment naked.  She thought for a moment, rolled her eyes and said "Really?"
"Yes" I said.
"Now?"  
I said "Yes, now."  

So she thought for her moment and went into the bedroom.  She came back out stark naked.  Back then she was young, tan, and fit.  She has a beautiful hourglass shape.  Her breasts move between a large C and a small D.  My favorite thing about her are her hips.  I'm not a big fan of the very thin boy body types.  Colleen is fit but she has a bum.  Anyway, she stood in the doorway and looked at me and shrugged her arms "Now what?"  I said "For starters, I'm starving.  Let's make some lunch."  So we made lunch, her nude, me oogling her the entire time.  I never missed a chance to smack her on the butt or goose her when she bent over.  All day I copped a feel whenever I wanted.  Finally at some point I couldn't take it any longer and I carried her off to bed.  Afterwards, we both spent the rest of the day naked.  

I thought it was a pretty great day so the next year I asked her for the same thing.  For 3 or 4 years she'd ask me what I wanted for my birthday and I'd look at her with one raised eyebrow and she knew what I wanted.  

Well, a few years in her old roommate came to visit us.  Sarah knew my wife very well.  They lived together for several years in college including at an old frat house with only one shower- a group shower with 7 or 8 stalls.  She told me that her and her friends used to lock the door and all go in there and shower together.  When I heard this, my head almost exploded when I thought about the visual.  Anyway, I digress.  Sarah came to visit us, but ended up living with us for a period of time.  She had moved out to Cali but had decided to move back and get a job in the area.  By this time both my wife and I had jobs and had room to spare for her to stay in.  Truthfully, I didn't mind.  Sarah was very cute and outgoing.  Like my wife, very confident and outspoken.  Having two girls around was great.  Having a new girl come out of the shower in a towel was a novelty.  They'd tan together in the backyard.  It got very comfortable.  I'd watch football and they'd do their nails together.  Sarah would be in the shower and I'd ask her if I could come in and pee.  She didn't mind.  Anyway, my birthday happened in the middle of this.  Colleen, my wife, said, "Well, I guess your birthday present is off for this year."  "Like hell," I said.  "Maybe you could get Sarah to shove off for the day.  Go take a day trip or something."  My wife told Sarah and she laughed (she knows me) and said she'd find something to do.  She decided to go camping and hiking in the mountains with a friend.  Of course, on that day it poured buckets and Sarah was forced to stay home.  That morning at the breakfast table she apologized and said she didn't want me to miss my special day, that she'd find something to do.  During breakfast I told Colleen that when she came out of the shower, she'd better not be wearing anything.  Colleen said no way will I do that.  Sarah said "Go ahead, pretend I'm not here".  Colleen said "No, that would be really weird."  Sarah told her that if it was her boyfriend she'd do it and that Colleen was no fun.  Now, I think my wife is fun.  But Sarah takes it to a different level.  Colleen knows this and is a little sensitive about always being boring compared to her friend.  Then we both started baiting Colleen telling her that she owed it to me and that she should really be brave and suck it up because I was such a great boyfriend.  And she didn't give me any present.  Sarah laughed the entire time she was making fun of Colleen.  It made it hard to be mad with her.  Also hard to argue with.  

When Colleen got out of the shower I heard her dry off.  Then I saw her peek her head out of the doorway.  We lived in a ranch with the kitchen next to the bathroom, oddly.  Anyway, both Sarah and I started cheering her on.  And she came walking out with her hands covering herself.  I was in heaven.  Sarah  basically laughed her ass off for getting Colleen into a tricky situation.  Colleen handled it pretty well.  After a fashion, she decided not to be embarrassed and went about her business.  Sarah teased her for a bit, but after an hour or so, it felt almost normal.    

Things had settled down and I wasn't paying too much attention when Sarah went into the shower.  She came out in her usual towel around the middle.  Colleen waited for her to talk by, then unexpectedly she pounced on Sarah.  Sarah screamed as Colleen ripped away most of the towel.  Sarah was trying desperately with one hand to maintain her grip on the towel and she was hedging her bets by covering parts of herself with the other.  Evidently, Sarah hadn't considered that she'd awakened a giant when she goaded Colleen into stripping down.  Finally Sarah ditched the towel and ran towards her bedroom totally naked.  I was treated to the sight of her white bum as she squealed and ran around the corner to her bedroom.  She also had her hands across her chest as busty girls are prone to do.  I was whooping and laughing like crazy.  Once in her room, Sarah threw open her dresser drawers to try to get ahold of anything to put on.  Sarah would try to put on a piece of clothing, but Colleen would rip it out of her hands with a grunt and throw it across the room.  After 3 or 4 minutes of this Sarah looked over at Colleen.  Her face  showed both determination and exertion.  They both stood there uneasily.  Colleen was laughing but gritting her teeth at the same time.  Sarah was cowering and trying to cover herself with her hands.  Finally Colleen broke the silence.  "Are you going to help me with the breakfast dishes?"  They both burst out laughing.  Sarah was still covering herself but walked back into the kitchen.  "Happy Birthday" she said.  

I'd seen Sarah in a bikini before, but this was the first time I'd seen her naked.  Both the girls were young back then, just out of school.  Watching them both standing there totally nude will forever be burned in my mind.  As they stood with their backs to me and washed dishes in the nude I just stared and tried not to say anything.  

At this point, I'd been dating Colleen for 4 years or so.  So a new naked girl was pretty amazing.  Sarah was a little bigger than my wife everywhere, basically.  She has a very pretty face.  Her body was good, but her personality really helped her out a lot.  Seeing the two of them in the apartment totally naked was the best birthday present I ever got.  I just stared at them for a while afraid to say anything.  When I finally got off my chair, I had to hold my hand in front of my pants.  Sarah saw and laughed.  I watched them clean up the dishes for a few minutes (I dried).  Afterwards, I got up and sat in the center of the apartment as they both padded in and out of the living room.  Finally after an hour or so, I told Colleen I couldn't take it anymore.  "Baby, I have something I'd like to show you in the bedroom."  Obviously she was determined to cause pain for both Sarah and myself because she was having none of it.  "No way" she said.  

"But baby, I really need your help."
"Why don't you help yourself?" she said.

I sat silent for a second because I was really, really hard.  I was also a little nervous about doing this in front of Sarah.  I thought about just getting up and taking care of business, but Sarah and Colleen were having none of it.  They both said that when I came out they'd both be dressed.  

"Then what?" I said, even though I knew what they were both getting at.  Colleen said, you can take care of yourself, but it's got to be out here.  

Sarah walked over to me and bent down to whisper in my ear.

"C'mon.  You know I'd love to see you jack it."

I said to them.  I may have to to it about 10 times in order to make him go down, I said.  Sarah rolled her eyes and said she thought it was unlikely that I could go on that many times.  I was sort of losing my will to resist those girls.  I really wanted to jerk off, but with 2 people staring at me I was a little self-conscious.  Finally, I took off my pants and underpants and sat on the couch.  Sarah looked at Colleen "Hey, don't we get to check him out?"