The C42 chute fires through the little hatch on the top rear fuselage, right behind the wing. They all have that hatch, so it doesn't help you identifying which have a BRS and which don't - only the stickers or the handle in the cockpit will clue you in to that.
Ours is a Junkers Magnum -
Airmasters- Aircraft Maintenance & Rotax qualified service engineer - rather than all being contained in a 'pod' there's a small rocket in the back (quite near the fuel tank) and a separate big black bag containing the chute.