Overview of Rituals (this one only apply for male espers), esper will create a clone of themselves using their ability and have sex with it, their psychic power will increase in the process, the ritual will end after they're out of semen, noted that multiple cums are allowed, thus, esper has to perform the ritual as long as possible, each espers only has one chance, being a strong esper or a weakling depends on their endurance...
Context: Red-kun's just doing some training, nyahaha🧊😼