Someone who can ruin a good time.
A person who will turn something pleasureable into something painful.
A person when attempting to give a blow job bites down on the dick.
Someone who will intentionally bite down hard on the dick to get out of giving a blow job.
To totally destroy a good moment.
"Dude this could have been the greatestnight of our lives! You just had to be a total cockbiter and ruin it for everyone!"