asuming you have a zombie chihuahua, a nurse and sebastion (for me the only 'if' there is the nurse) it goes like this
0) deploy with mcmorning nurse and sebastion in basecontact witht the chiuhuahua (or at least in melee) and more importantly nurse in base contact with seb and mcmorning.
1)activate nurse, cast massive dose on chihuahua, using painkillers (wont die)
2) activate seb, make three melee attacks on the chihuahua, hoping for/cheating crows for piece for me.
3) use (0) 'for you master' (give McM the BPs)
4) activate mcmorning, cast wrack with pain, using masks from hand or (if your lucky) flips to trigger scalpel magic for free strikes, also use a BP to gain fast if you have a 6+ any suit to guarantee a wrack cast as there is a chance to flip a mask triggering scalpel magic, use (0) for scalpel slinging
5) activate dog, use warck with pain on mcmorning (hes gone so no (0) wont hurt, and 2wd is easy for him to shrug off) and then sack for 2BPs
using this sequence the worst payoff (including black joker on an attack flip from Mcm's scalpel sling and a failed cast of wrack from the chihuahua) is; seb-0 (no crows in hand, no crows flipped) McM-2 (no masks and a BJ on the slingin) chihuahua-2 = 4 BPs, however the bad luck required is fairly bad however it does highlight this method is fairly suit dependant
Absolute best outcome (3 crows for sebastion, 3 masks for McM) is; seb-3, McM-6 (3 wracks, 3 hits from scalpel magic, 1 slingin attack and -1 for fast), chihuahua-3 = 12 BPs from a 1ss model
I have used this a few times and I must say unless you have some devious plan for the nurse (im looking foreward to using sues shrug off to great effect ) this trick doesnt realy warrant taking one, especialy as she ditches harmless in her first activation. also it is quite suit dependant i can count on one hand the number of times ive got 11 or 12 BPs from this, however i quite often clear 9 (did somebody say rogue necromancy!) and definitely clear 6 (flesh construct + fast). in most scenarios this isnt a viable tactic without a post-dog-mullering plan for the nurse besides dog missles (never worked for me) and you can get screwed by bad suits (oh how I love playing rezzers!), however if your looking for a theoretical limit on BPs form a chihuahua id say 14 (12 + 2 from a double punch from rafkin) but that list would be wholely based on doing it, not for playing a game.