A sexual act, usually performed by male virgins, whereby they incorrectly slide their penis between the woman's thigh and bedsheet, and think they are having vaginal intercourse
"This blokethought he was inside me, but he was thigh-sheeting. I let him have it"
(in science class)
Aaron: The teacher can eat crap
Teacher: Aaron, you may leave my class and we will talk after class
A student: Aaron just got yeeticus skeeticus deleticused by the teacher