When you are in the act of coitus and a guy or girl (because it could go both way) sticks their hand into the girls' vagina for the pleasure of the girl. Similar to fingering
1. Sebastian "Dudeee, last night I was with this fox and I stuck my hand in the cookie jar" ;)
2. Bianca "Hey girlyyyy, last night I was with this HOTTT guy and he stuck his hand in the cookie jar!"
2. Bianca "Hey girlyyyy, last night I was with this HOTTT guy and he stuck his hand in the cookie jar!"
by themostpeppermentofcanes September 25, 2015
"Uncle Joe got caught with his hand in the cookie jar while trying to grab a toy intended for the kids".
by Dan Drzewiecki November 04, 2003