1)adj. Refers to the fat which "spills" out over the top of a (usually, although spills can be male as well, if the spilling is that revolting) female's pants. Such breeds of this animal that have been officially documented include: the double spill, the 270 degree spill, the 260 degree spill, the half spill, the vaginal spill, among others.
1. When a woman spills all over; it means that she is/was VERY sexually pleased that she came so hard and so much that it just spilt out, gushing all over. In other words, you just gave her a six lip smile.