Acronym for Look-At-Me Bisexual. An attention-seeking device, becoming more and more prevalent as (female) homosexuality is becoming more tolerated. Generally practiced by younger women who can still pass off such behaviour as being "sexually confused" or "sexually explorative."
A female who seeks attention by loudly proclaiming she would engage in sexual acts with a member of the same sex, if only to gain attention from males. LAMBs may or may not actually enjoy such an activity, but will engage in it if they think it will enhance the reputation, namely, their sexual status - this implies that men may have a chance at a threesome. Whether or not the subject would actually sleep with men for whom the performance is put on for is another matter. Generally, being seen as bisexual is just as if not more important than getting laid.
A classic sign "making out" with members of the same sex. Others include pornography typically aimed at men adorning walls, computer wallpapers, screensavers, etc., or "casually" pointing out how they would like to sleep with another nearby female.
A classic indicator which differentiates this from true lesbianism/bisexuality is if the female in question is no longer at the centre of attention in a social situation - loud comments of a bisexual nature, or any of the above signs are suddenly made in attempt to regain the focus of the social group.
In rare candid moments, the subject may actually admit to not really desiring members of the same sex, and that they don't actually enjoy the behavioural practices they see as necessary to maintain social status.
Term originally coined by the lith.
"L dragged my up to her room to show me her new Playmate centrefold. Wouldn't shut up about it. But last week she got depressed and told me she hates making out with chicks. She's a such a fucking LAMB."