Two shut-in otaku become friends over two-dimensional stuff and try the nipple training they learned from erotic manga. He cannot stand her no-bra tits. He sees the raw nipple bumps and kneads the huge breasts. He flicks the nipples that harden in the center of the tits until her breasts shake and she cums from the nipples. He keeps working the sensitive nipples until she sinks into a nipple swamp. Their curiosity about sex climbs. They spend themselves on nipple-play sex until his sperm runs out and he creampies her again and again.