One of the few 3 letter phrases that has yet to be defined on Urban Dictionary. It can stand for: 1. Porn Quality Bad, 2. Poor quilted beggar, 3. Pop-quiz BITCH!!!, 4. Puny queer's boner, 5. Placid quacking bear, 6. Phony Quiddich badge, 7. Please quit boningmeintheass, 8. Paris quietly/quickly blows, 9. Phat Quisnos Bong/Burrito
Many other uses will be found in time, as is custom for everything on Urban Dictionary, the one true God.
I just had a pqb all over your 15-year-old pregnant girlfriend's face!!! Semper fi, motherfucka!