When adorned in a full ninja costume, the act of approaching a blind civilian and swiftly inserting (no more and no less than) three fingers into said civilian's unsuspecting rectal cavity.
"Hey, look at that blind guy! I'm gonna hook him up with a sneaky tank job. He'll never know what hit him!
A sneaky Hastert involves performing an unwelcome sexual act, under the pretense of performing some other helpful action. The name comes from former house speaker Dennis Hastert, who allegedly molested members of a wrestling team he coached, under the pretense of assisting with the treatment of sport related injuries.
Person A: My groin cramped up in wrestling practice again, and the coach offered to help me stretch it out.
Person A: It would have been, but while I was writing in pain, he jacked me off and fingered my asshole, then ran away while laughing maniacally and sniffing his fingers.
When someone (guy or girl) is asleep and a guy jerks off and finishes on them (without them waking) and then they proceeds to take a paintbrush and rub it in.
Last night I gave Ally a sneaky paint job she woke up and thought someone put glue on her