When someone is stabbed in a particularly meaty / fatty region of their body, it is noted as being a "Flab Stab". The buttocks, abdomen, chest, thighs and underarms are all places which contain a sufficiently high fat percentage to be regions where a "Flab Stab" is a possibility.
The knife was thrusted into Dr. Evil's buttocks at high speed, gushing blood and fat outwards. Dr. Evil slumped to the floor, motionless.
"Aha! So even the greatest fall from the Flab Stab!" said Mr. Raminov.