Literal translation: Manifestation art (obviously fullbring is better, right?). It is an art of maximising the capacity of an object you hold dear by pulling out its 'soul' and resonating it with yours. It could be anything as every object has a 'soul'. Hence the object with which you're most functional is called your FullBring
Girl: (exhausted) That was great, Melissa! How did you do that?
Melissa: I thought I told you, this strap-on is my fullbring.
verb. A technique used to prolong the act of sexual intercourse. Prior to male ejaculation, the cremaster muscle retracts the testicles into the body. To prevent the subsequent ejaculation, the testis may be manually withdrawn from the body.