A man laying his forearms flat on the ground in Sujud is listed among the disliked postures.

Disliked Acts in Prayer, Part 1: Movement, Clothing, Recitation, and Posture

• They must immediately cut their prayer.
• They should try to suppress it, and if unable, cover their mouth with the back of their hand or sleeve.
• They must recite the Takbir aloud.
• They must prostrate immediately.