The chocolate runway is the long-lost art of shitting down one's throat in such a way that it slides right down, leaving a 'chocolate runway' behind it.
"Last night Jason gave Emily a chocolate runway and she was talking about it all morning!"
where david likes victoria to shove her fist
david: "make sure you spit on it first"
vic: "maybe i can stick my fingers down my throat and throw up on it instead?"
david: "okay then hunny, be gentle..."
vic: "brace yourself david"
david: "ohh, that was just like last time, only better"
vic: "thats cos it was Brooklyns head"