A word one would use as an excuse to complement or comment on the front logo of a t-shirt of a female if he (or she) is caught looking or staring at her boobs.
Also people could say that to accuse others for blaming them for looking at their boobs when they were looking at the boobs or were not looking at the boobs.
Other words may be El Aye Em, Lammin', or Fuckin' Lamz.
Huh? Ohh I was just looking at your cool ass shirt. Why?
Ohh ok. Just had a LAM.