When someone is receiving a blow job with the persong giving the blow job has a packed lip of Dip ( Dipping tobacco ). The tobacco ends up all over the person's penis
Guy 1: She gave me head, but she had a mouth full of Skoal.
Guy 2: Oh man, she gave you a Sloppy Dallas.
Example 2:
Guy 1: Billy Jim offered me a blowjob for some Taco Bell, but he has dip in his mouth.
Guy 2: Ah hell man, that would have been one helluva Sloppy Dallas.
"Hey Matt, you in the mood for a Sloppy Dallas?"
"Babe, I've told you this a million times, I don't want my dick to look like I just fucked a lawn mower bag."