I went into Blackwing Lair recently with a guildie and came out with a new skin colour for Cerberus:
I have to say, duoing BWL with a boomkin is pretty easy - Razorgore gave us the most trouble, but the rest is pretty much a faceroll.
Razorgore: if your partner is controlling Razorgore, keep Mend Pet up to help grab aggro on all the mobs and stand just below the platform so that you can quickly pick up any mobs running towards the orb. I found using a tenacity pet in MM spec the most helpful; if you get low you can hit Chimera, but I mostly relied on traps. Staying in Aspect of the Fox helps to keep your Focus up - you don't really need the extra DPS Hawk provides.
Everything in between: Tank n spank. If you want to tame Chromaggus, just stand at max range and go for it; no tricks required.
Nefarian: Using an heirloom ranged weapon will completely negate Nef's hunter class call, so you won't have to worry about your bow breaking. In phase 1, it's easiest to let the mobs come to you and kill them all in a pile rather than picking them off quickly, so that in phase 3 they'll all rez in the one spot. Being in BM spec can be helpful for breaking you out of fears occasionally. Be mindful what each of your raid member's class calls are and act accordingly.