Coined in Toronto Ontario, this phrase has begun to spread rapidly. The phrase essentially means don't try to talk if you can't walk the walk.
Note: There is no stress in the wordsboop and poop...when pronounced sounds more like bewp and pewp
Hypothetical situation...Someone claims they can bench press 300 pounds when in reality they can only do 200...Response would be: Yo...don't boop if you can't poop.
Boogie woogies make this claim constantly when they are confronted about their future. They make plenty of money with their form of three r's (robbin', rapin', and riotin'.)
Tyrone addressing the school principal: "Hey moefoe! I don't like school. Don't need no booklearnin'."
Don't judge a book by its cover basically means that you shouldn't judge before you know, you should't judge because 9 times out of 10 the reality is different than you think
Old dude: He has dreads and tattoos, he must be dangerous!
Youngin: Don't judge a book by its cover.