From the "Poetic Imagery" section of our Dictionary of Semenyms:

magical mixture - an enchanting concoction; used to describe semen as a miraculous thing, suggestive of alchemy; see also magical fluid. “For a guy with a pecker as long as Terrell’s, it takes an extra amount of time for him to cum as his cock convulses and propels the creamy, magical mixture out of his peehole.” —Sandmann