"When the Messenger of Allah would lie down, he would place his right hand under his right cheek, and he used to fast on Mondays and Thursday." (Using translation from Nasāʾī 2367)
«كَانَ رَسُولُ اللهِ ﷺ إِذَا أَخَذَ مَضْجَعَهُ وَضَعَ كَفَّهُ الْيُمْنَى تَحْتَ خَدِّهِ الْأَيْمَنِ»