LMC is a method devised by Ethan DeGroote and Jason Thomas. The method is similar to the CFOP method - in that you build a cross, do F2L, and have a last layer - but this method involves "being lazy" with your cross, hence being named Lazy Man's Cross, and only solving 3 of the cross pieces and putting an edge of the opposite color of your current cross color into the last cross slot regardless of its orientation. You build the rest of the first two layers any way you like and then perform one of 16 (18 in the full version) algorithms to orient the edges of your last layer (preserving whatever corner orientation and permutation you have at that moment) and solve the last edge piece simultaneously. This might not sound like the greatest approach at first, but you can usually save moves in the beginning or just put less effort into a difficult cross. When paired with some last slot methods it becomes a pretty versatile method - considering that you always end up with your edges solved when you reach the last layer.