When your shlong is inside of a vagina totally. It is when you are in far enough that your balls are touching her asshole.

failing to complete a task succesfully

Yelled by Denver broncos fans..when a pass is incomplete...

The male falling asleep during intercourse in the missionary position. Usually occurs after a night of drinking.

Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.

A way for parents to explain what they were doing without explaining what they were doing when their kids catch them doin the do

When you and your partner can't "finish" the deed.