This word bight (from m-w.com)?
Main Entry: bight
Etymology: Middle English, from Old English byht bend, bay; akin to Old English bugan to bend – more at BOW
Date: 15th century
1 : a bend in a coast forming an open bay; also : a bay formed by such a bend
2 : a slack part or loop in a rope
Exactly what is bad about one’s butt being in one, except for 1) it might get wet, or 2) um, some sort of rope burn?