Granny Handing 

Cumming on your hand, waiting for your hand to dry then working that crusty shit again for ultimate friction.

OR

Swimming for long enough for your hand to become wrinkly, then jerking someone off with your pruney fingers.

def. 1.
DUDE 1: hey dude shake my hand!
DUDE 2: ergh! your hands are crustier than kingsmill! you been granny handing?!

Granny Handing by Los Hombres, Dos August 5, 2010

Granny Handing 

When your fingering a girl for so long that your fingers get pruned and wrinkled.

“Hey why yo hands look like that”,
“Oh I’ve been granny handing my girl”

Granny Handing by BearWithGun September 9, 2019