An event, action, comment, person, or process that's so fucked up, it stops you in your tracks literally or figuratively, or at least makes you shake your head in genuine shock and awe (can be noun, adjective, or verb)
I was entirely stunfucked by the 2016 election
That dude is an absolute stunfuck, 24/7
When a girl gets fucked for a long-time, typically a virgin 18/19 year old asian girl and often by more than 1 guy.
"18 year old Japanese girls don't get stunfuck - ed for 75 minutes by 3 guys"