He will remember that forever.

My older sister (38) and her husband (40), Her bestie (36) and her husband (Unkown) and myself (23) all went out for my BIL's 40th, My sisters best friend who I know very well was our DD because she was 8 months pregnant, So we ended up getting waaaayyy wasted and on the drive home which included 14 miles of gravel roads my sister and I were in the back seat with her husband sitting between us so me and her could each have a window seat incase we needed to throw up.
My sisters bestie's husband was probably the worst out of all of us and was passed out hard in the passengers seat, My sister and I are half sisters with the same dad and different moms and as such are built very differently, She is 5'3", Average build with small **, I am 5'10" and skinny with DDD's, Her bestie is about 5'6" and normally a C but currently DD.
We were driving along and laughing and talking, Dancing in our seats etc. and my sister blurted out something about her husband having a big D, He laughed and my sister said "Whip it oooouuuut", We had just pulled up to an intersection and her friend stopped, Put the vehicle in park and turned around saying "Hold on, I'm not going to miss out on this" and we all had a good laugh at that, He is over 6' tall and he's a big guy, Big, hands, Big feet and a decent build. He undid his pants and whipped them down, I was not expecting that at all and was like "Whoa!!!!! WTF?", My sister and her friend burst out laughing and my sister looked at her friend and said "Told you", and her bestie said "Good gawd...You poor girl".
I was sitting quietly staring at his...Manhood, We were sitting parked at an intersection on a gravel road in the middle of nowhere, My sister and I on either side of her husband, Her bestie turned completely around facing us with her big, Pregnant belly resting on the center console all looking at his huge D, My sister said "He's 8" and a trojan magnum is too tight on him" which I knew was a huge condom because my friends and I researched it, My sister reached over and grabbed his shaft and said "Look" and showed us the gap between her middle ** and thumb, She said "You have long fingers...Try it" looking at me, I coughed and said "Ahem, I don't think...I...Ummm" and she said "**, I am drunk enough this will probably be the only chance you ever get so...Do it".
I looked at her bestie and she raised her eye brows and nodded, I slid my hand under it laying against his stomach and wrapped my fingers around it and even my fingers which yes are longer than hers didn't touch, My sister looked at her bestie and said "Check it out" her bestie looked at her husband sleeping in the passengers seat and said "You don't have to try to convince me" and grabbed his shaft saying "Good lordy" She smiled at him and he was staring right in her cleavage She looked down and said "You'll probably never see me with cleavage again once I have the baby so take a look".
My sister gagged and said "Oh **, I need some air" and rolled her window down, Her bestie looked at me, I shrugged and my sister leaned out the widow, After a few deep breaths she looked back and said "Carry on...Don't mind me", and then...Her husband put his arm around me, I was like "Oh **" and then next thing I knew her bestie was stroking him, I was massaging his ** and my sister was laughing and intermittently puking out the window, My sister got on her knees leaning out the window and her husband slipped my dress strap off my shoulder, I was nervous doing it in front of my sisters bestie but I let him since she was already jerking him so next thing I know she takes my hand and I am jerking him, He's got my dress around my waist and my bra off, he leans over and unzips her besties dress and she whips hers out, Big, and firm and veiny with big dark nips which surprised me because she's pale skinned like me, He's playing with both of our ** and we are jerking him, He slides a hand between my legs, Luckily I wasn't wearing ** on that night and slips a ** right in me, I don't know if he has magic hands or just knows what he is doing because it was like a minute and I frickin clenched my thighs and came, Right after he stood up and leaned over my sisters bestie and hiked her dress up, She got wide eyed and went for it, She opened her mouth and he shoved it right in, I slid down onto the floor between my seat and hers and leaned in licking the shaft and ** as he started ** her, I could hear how wet she was and how fast he was hammering her, I don't know what came over me because I am 100% straight but I twisted my head to the side and started licking her nip and she moaned and said "Oh no, No, No...Wait..." then I pulled back and watched her eyes roll back and then I heard...Literally heard the splash as she moaned, his huge D slipped out of her mouth as she moaned and I went for it sucking him, He got one knee on the seat and leaned me in so me and her were taking turns sucking him and playing with each others ** and then he grabbed my head and shot a huge load in my mouth, He pulled out fast and she scrambled forward as he shoved it in her mouth and came again, He went back and forth until we had both sucked multiple loads out of him and he finally went limp.
He sat down and we were all super embarrassed but we were all giggling, He said "One last thing...Kiss for me" and we just did, Me and her with our ** out kissing in front of him. We cleaned ourselves up and he got my sister back in the car, We dropped off her besties husband first and my BIL helped him in the house then we got to my sisters and he carried her in the house, Her bestie had come in and we were all standing in the mudroom as I was staying the night there and she was heading home but he asked if she was ok, She said she was embarrassed and wanted to know if we could keep it between us, We all made a pact to take it to the grave and then she looked down biting her lip and he led us both by the hand to the spare room and long story short we had a threeway. Me...My BIL and my sisters 8 month pregnant bestie, First time ever for all of us, First time ever licking a girl for me, Second time for her and first time ever I squirted, I don't even know how many times he actually finished but I can say 2 for sure one in my mouth, One in hers and I am reasonably certain at least one in me.
I have carried this for 3 years and wanted to tell it but never could until now.