Where someone who is a sleep gets hit in the face with a pillow or another swingable object near a bed e.g. a bed side table. But pillows are used the most
Also to get pumped/farted in the face when a sleep peferably in a sleeping bag.
You got a slabadash last night dik ed.
Hitting someone across the face in one large swooping horizontal direction with your penis. Leaving a red mark on occassions.
Instead of using offensive language, Mark pulled out his penis and gave Lucy a trademark slabadash in the face, leaving a large red inprint