Indeed, "prison sex" is often the preferred method of sex in prison, where quickies are key. It is not to be confused with conjugal visits, which imply no particular sexual positioning between partners.
"I like to look my fuckee in the face, Dude. Prison sex to me is all about efficiency and nothing about romance."
"Believe me, if you both want it bad enough, you'll find a way . . . maybe several different ways."