Cracked a fat 

Commonly used Australian term, to obtain an erection. Can often be used as an insult in a comical sense.

Moff CRACKED A FAT!!!!!

Cracked a fat by joe22 November 11, 2004

cracked a fat 

To gain an erection,male penis becomes long and hard.

on looking at your girlfriend i have cracked a fat

cracked a fat by manwithwalkingstick May 13, 2005

cracked a fat 

To gain an erection

I seen her panties as she bent over and I cracked a fat right there and then.

cracked a fat by bl4cK October 20, 2008