From the "Quantities" section of our Dictionary of Semenyms:

strands of tinsel - glistening threads; used to describe semen as a festive decoration, suggesting a Christmas tree. “Presently he began to spurt, some of it into Michael’s constricted throat, and the rest of it, the massive main surge, into Michael’s face and hair where it hung like strands of tinsel before falling against his shoulders.” —Anonymous