What are good sexual acts? It is not that surprising when cultural voices, without reference to God, argue for the inherent goodness of all “unharmful” sexual desires and acts. Regrettably, ethical pragmatism has influenced some Christian sexual ethics, and this influence is particularly evident with the issue of masturbation. What God defines as good sexual acts are those that fulfill his unitive and procreative purposes for sex within marriage. Given God’s unitive and procreative purposes for sex within the context of marriage, we argue that masturbation is a categorically impermissible act because it fulfills neither of these purposes, and we counter Christian arguments for its permissibility. God calls Christians to deal with sexual desires, including good sexual desires, through either marital sexual expression or Spirit-enabled self-control.