Anal sex is one of the major sins in Islam and Allah has cursed those who do it! If he forces her to do this, she must refuse and resist and if needed, take him to court if she can prove it.

Kindly refer to the following link(s):

https://www.assimalhakeem.net/is-oral-sex-allowed-in-islam/

Is oral and anal sex allowed in islam? If not what should the wife do if she is forced by the husband to do so ?