Bow wow wow yippy yo yippy yay, bow wow wow yippy yo (the bomb)
Bow wow wow yippy yo yippy yay, bow wow wow yippy yo yo yo yo yo yo
Chorus from Snoop Dogg's Who am i (what's my name)?
It has been sometime since I connected a subwoofer to a receiver with no sub output but I believe you connect speaker wire from your receiver's outputs to your subwoofer's speaker inputs. Then you take another pair speaker wire from the subwoofer output and connect it to your speaker inputs.
Something like this. You would be utilizing the crossover of the subwoofer.
http://www.outlawaudio.com/products/lfmcompact_gallery3.html
You are a nice Dad to accomodate your son's love of rap music. My parents weren't so accomodating till I tried to improve the bass on my Dad's ADS speakers by swapping out the stock woofers with Pyle subwoofers. When I damaged his amp and the ADS crossovers he finally got me a better sound system but only after grounding me for almost 6 weeks.
Good luck.