High raping is when you take advantage of the fact that somebody is high by asking questions or requests that you know they would not answer or do if sober.
"Yo did Tommy really take a pinkie in the bootyhole?"

"I don't know man, he won't tell me. Let's high rape him to find out."
by Mooncock Bumberfuck February 25, 2018
The unlawful compelling of a person through physical force or duress to give a high-five.
Elise: Katie, gimme five!
Katie: Dude, no way, I've already fulfilled your daily quota of high-fives.
Elise: (grabs Katie's hand and slaps it)
Katie: I feel so violated...
Kelley: And that, kids, is high-five rape.
by Ke'Elso December 17, 2008