The real meaning is Wet Ass Pussy but just incase your Facebook mum asks what it is, say Waffles And Pancakes.
Mum: What is "WAP?"
Me: (Panicking) um, Waffles And Pancakes.
Mum: Ok thanks
Mum: Posts on Facebook "I'm about to treat my husband some WAP today."
Me: WHAT THE FUCK MUM!