Oh god, me and my guy used to do that and it felt so good it almost killed me! God, it was good! I sat in the chair and pulled my knees up to my chest and the angle that his dick was at or me pressing my butt against the chair or something caused my vagina to feel real tight-every movement his dick made made us throw our heads back and groan-it was just so incredibly good. He couldn't really thrust because I was so tight but it was so intense-damn. I still have that chair too. Damn, that was good.
One time on holiday me and a bunch of mates met some wonderful girls. They were in a branch of show business and were really intelligent and talented. One of the girls had an exotic name (at least to my ears) Her name was Yola. She took me to an empty theatre and sat me down on a seat in the stalls in the dark. She sat on my lap facing away from me (yes, I am that ugly!!) Yola raised her skirt, pulled her panties down and bounced on my willy. She was sweet and sexy and WOW! Chair sex was an incredible experience for me