About yawning

It is said that the Shaitan laughs at us when we yawn. That's why I have a habit of suppressing my yawn by covering my mouth with my right hand. Do you still suppress your yawn when you are then sleeping already? Or is it okay to yawn when already sleeping?

When a person yawns, he should block his mouth with his hand as Shaytaan enters, i.e. the mouth.

(Sahih Muslim vol.2 pg.413; Rashidiyyah)

When a person sneezes and praises Allah, it is a right upon every Muslim who hears him that he replies to him and as for yawning, it is from Shaytaan. So, he should try to stop yawning to the best of his ability. When a person yawns results in a sound haa, Shaytaan laughs at him.

(Bukhari vol.2 pg.919; Qadeemi)
https://islamqa.org/hanafi/askimam/28519?_e_pi_=7,PAGE_ID10,9502181311

Thank you so much. May Allah bless you and the Ummah.

Abu Hurayrah reported that the Messenger of Allaah (peace and blessings of Allaah be upon him) said: "Sneezing is from Allaah and yawning is from Shaytaan. If any of you yawns, let him place his hand over his mouth. If he says ‘Ah, ah!’ (makes a noise when yawning), Shaytaan laughs from inside him." Abu ‘Eesaa said: this is a saheeh hasan hadeeth. (Sunan al-Tirmidhi, no. 2746; classified as hasan by al-Albaani in Saheeh al-Jaami’, 4130)