Let's see some videos of a guy smacking, stretching, jiggling, and bouncing a girl's butt like in the following examples.
#2
http://bigtitsroundasses.bangbros1.com/gal/247/p/keez/
#2
http://assparade.bangbros1.com/gal/132/p/keez/
#2
http://assparade.bangbros1.com/gal/120/p/keez/