Karrk
The clenching of your glutious maximus (butt muscles). When you sense the presence of a foxy specimen who is eyeing you from across the room (and wants to make love in the club).
" She be karrk'n her bunz off"
" She be karrk'n her bunz up and down, up and down"
" She be karrk'n her bunz up and down, up and down"