Thanks for your question.
The Bible is silent on this topic. However, Jesus said, "He who looks upon a woman to lust after her, commits adultery with her in his heart." (Matthew 5:28). I doubt that a person can perform this act without fantasizing about fornication and/or adultery. Indeed, with the explicit material available designed to seduce people into this activity, not much imagination is needed anymore. So, the answer is that, no, masturbation is not specifically mentioned. However, there are other principles of Godly living which are violated in this activity and make it virtually impossible to do without entering into sinful behaviour.