What is Sneaky Bastard?
1.
before you finger a girl go to the bathroom then get jizz on your finger then finger the girl.
Dude i gave that girl a sneaky bastard last night
See
2.
A guy who cheats quietly on his girlfriend behind her back and doesn't want be embarassed later, cause wants to get benefits on her.
* Someone who cheats on someone behind his/her back.
She loved and trusted him totally but that selfishness sneaky bastard cheated on her behind her back with other girls.
See