R&B singer B. Smyth was arrested during a traffic stop last weekend when he got loud with an officer, telling him that he was going to have sex with his wife. Oh, boy.

B., B., B.  -- Brandon Smith on all legal docs and to his mama -- if there is one thing you don't do during an encounter with a cop, it's mouth off. And you don't say you are going to mess around with his wife. That's asking for trouble.

TMZ got its mitts on the arrest report, which indicated that Smyth, 21, was pulled over for tailgaiting in Coral Springs, Fla., on Sunday, Dec. 22. Smyth was not interested in accepting the traffic citations, instead saying he was pulled over in a case of racial profiling.

He cursed at the cops and said he was going to sleep with one of their wives. We suspect his language was a bit more colorful when he said that, though.

Smyth would have been ticketed and free to go on his merry way, but he was insistent about NOT leaving the gas station in which he was stopped, so he was arrested for trespassing.

What a headache.