A homosexual sex act in which two male partners put the tips of their penises up against one another, and ejaculate into each others' urethras. Not to be confused with cum swapping.
The verb form of this term is "to exchange semen."
After they were exhausted from pleasuring each other but still had not yet ejaculated, Danny and Jared performed a semen exchange with each other.
"I just love how you fuck me, Danny! Now let's exchange semen."