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 B: Oh, that was helpful.
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.
Person B: Ah, the old sneaky Hastert.
Person A: Yeah, I feel so violated.