They are costly and he can only make so many a day. This might not be pure spite since the female is still unmated and the second male may encounter her later. In other species, males cap the pseudo-phallus with his own spermatophore. Female picks it up instead. B. Acanthocephalan worms.
Males apply cement-like copulatior plug to female genital pore after mating.
Males will also approach other males and rape them. No sperm are transferred, but the cement is smeared on the genital opening of the other male sealing it shut so he can no longer reproduce. In the bug, Xylocoris, the male pierces the female body wall and injects free sperm into her body cavity. The sperm then swim to the oviduct, enter it, and fertilize the eggs. Occasionally, a male will forcably inject sperm into another male.