"I went to Wendy's, ordered myself a crispy chicken sandwich and a double stack and then made myself a stacks-on-deck-wich. Holy shit, that was awesome."
A dance move; when two people's legs, normally a girl and a guy, intertwine in a "sandwich" fashion. This is when the two are facing each other, and the legs slip into this position: girl's left leg, guy's right leg, girl's right leg, guy's left leg; vice versa.
Person 1: Yeah I was getting pretty comfy between his legs on the dancefloor before we hooked up.
Person 2: So you guys did the leg-wich?