If in club/bar, when a guy, places his arms on your shoulders and whispers to you, "I want to pee so bad." do you think he is giving you the signal that he wants to make out in the restroom? Please answer
So much else goes into it. What kind of look does he give you? Is there a "come join me nod" in there somewhere? Do you find him attractive? You could always say, assuming you want it to happen, I gotta go really bad too and go and go from there. My guess is his cues will let you know from there?