Tenshi no harawata: Akai kyoshitsu (1979)

Starts with the blonde on all fours, inked-up back arched, taking it doggy style from a ripped guy. Camera catches every thrust from the side—you see his muscles flexing as he grips her hips. Then the brunette joins, same position but facing the other way, so both girls are getting pounded at once. Lighting’s all red and moody, makes the tattoos pop. One girl’s got a thigh piece that wraps around her leg, gets highlighted every time she moves. Switch to missionary later, but the DP part’s the money shot—guys really going at it, no holding back.