There is no question in it that it is totally haraam. Having intercourse with one wife while another is present there and can see the action is totally haram. With regard to threesome, it is a western way of living that has nothing to do with Islam and a Muslim. It is very lowly act and should not be even thought about.
The sahabah and early scholars regarded wajs(having intercourse with the knee and the other can hear the sounds) is makhroo. By makhroo they meant haraam.- al-Hasan al-Basri.
Narrated by Ibn Abi Shaybah in al-Musannaf, 4/388
Ibn Qudaamah (may Allaah have mercy on him) said: If two wives agree to live together in one house, that is permissible, because they each have the right to their own house, but they may give up that right. Similarly they may agree to let him sleep between them in one bed. But if they agree to let him have intercourse with one of them when the other one is looking, that is not permissible, because it is vile and despicable and is not appropriate, and it does not become permissible even if they agree to it.
al-Hajaawi the author of Zaad al-Mustanqi’said: It is makrooh to have intercourse where anyone can see.
The thing as such as Threesome covers three issues. The first is having intercourse where awrahs of both parteners can be seen. It is obligatory to cover awrah and showing them to the third person is haraam.
Secondly intercourse must be had in a place where the awrah cannot be seen. For example, if they are covered with a blanket and he starts to have intercourse with her, and the movements can be seen. This is undoubtedly more likely to be haraam, because it is not appropriate for a Muslim to lower himself to such a level.
This may provoke desire in the person who sees this and may lead to evil consequences.
The correct view concerning this matter is that it is haraam to have intercourse with a woman in view of anyone, unless the onlooker is a child who does not understand what is happening; in this case it does not matter. But if the child understands what is happening then intercourse should not take place where he can see, even if he is a child, because a child may speak about what he has seen unintentionally.
Sharh Kitaab al-Nikaah min Zaad al-Mustanqi’, tape 17.
And Allaah knows best.