A romantic relationship between two individuals with the intention of sexual gratification/procreation. The closest human equivalent is 'to be in love'.

A person in a matespritship may be referred to as 'matesprit'.

Also known as the flushed quadrant of the Alternians' relationship quadrants (MS Paint Adventures by Andrew Hussie).

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life