Mad, or stupid.
Welsh slang. The phrase originally comes from the action of having tapped a barrel of beer, draining its contents. The comparison made, then, is between a half-empty barrel of beer and a half-empty brain.
"Watch out for him, he's tapped."
"Are you tapped or what?"
To hit one with the meaty part of your cock.
"Albert, I'm gonna Meat tap Alex."
To hit someone (or something) with your meaty cock.
"I'm going to Meat tap Alex!"
When you fuck your mates girl friend becuase he stole your beers
Fuck man, stu stole like all my beers last night im gonna tap tap revenge him
Tapping someone's left shoulder while standing on the right, or vice versa.
Bob just alternative shoulder tapped Susie.
Someone who lies or says something that really couldn't possibly happen.
Teacher: And that's why x=y
Boy: No it's Z you gas tap!
2
Boy 1: I heard Sally went out with Mike on Friday
Boy 2: No she didn't, you gas tap.