@tanukihat
Why wouldn't he? It's worked before. He just has to keep slashing until he either accidentally or actually finds the source of multiplication like when Boros invaded.
@tefuya spermicidal lube, a sock, a keenex, being outside of the human male for an extended period waiting until their life span is up. There are lots of methods to kill sperm that comes from out own body. But what about sperm that used to be human?