Does the insertion of a small part of the head of the penis into the anus constitute sexual intercourse, and does it necessitate expiation?

Approaching women in their anuses is forbidden and a grave major sin. There are narrations describing the perpetrator as accursed, stating that Allah will not look at him, and that whoever does so has disbelieved in what was revealed to Muhammad. It is permissible to enjoy the outer part of the wife's anus as long as it does not lead to approaching her in the anus. Sincere repentance is obligatory for whoever has committed this act.