An R-rated Red Band trailer for an anarchic, no-holds-barred sex-among-the-summer-camp-staff training session that turns into a freaking “Friday the 13th” slasher comedy.

Finn Wolfhard and Billy Bryk co-wrote it and star in “Hell of a Summer,” headlining a cast of fresh young faces (Pardis Seremi, Abby Quinn, Krista Nazaire, Julia LaLonde, D’Pharaoh Woon-A-Tai).

Neon has this edgy/funny/bloody romp set for April 18.