Shaqiq (may Allah have mercy on him) says that Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: None of you should ever prostrate leaning on his buttocks or hip, nor prostrate lying down, for when a person prostrates well, all his bones prostrate.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2716