What is the ruling on one who touches a child's buttocks with his penis without ejaculation?

Whoever does this with lustful intent must repent, feel remorse, and strive to keep himself chaste through permissible marriage. If he is unable to afford it, then he must fast. The precursors to indecency, such as deriving pleasure from kissing an beardless youth, touching him, and looking at him, are forbidden by the consensus of Muslims.