its your reaction to something embarrassing

when your little brother thinks you are a low life

>>28778932
cringe
verb
1.
bend one's head and body in fear or apprehension or in a servile manner.

Something that bothers you so much that it is almost physically painful

>>28779201
Just rape the little bastard

When you feel sense of second hand embarrasement. When you feel awkward for the other person. Usually when you see someone say or do something stupid, you might react to it physically by biting your teeth and making a hissing sound.
Cringe is a sign of empathy.

To suck my dick

any and all autistic behavior