In a BDSM role play ( slave-master) is it shirk to bow down to the other person as a form of a sexual gratification? ( I wont go in detail as to why a person would do that, as the fetish can be looked on online, it is a well known fetish) The person knows that there is no God but Allah and fully accepts it.I think this is a popular fetish and there is no clear answer on the internet. This fetish is difficult to get rid off and I would like to know the ruling, whether it is shirk or not since if its shirk then people would have to quit right away if not then people can strategize how to weaken the fetish. . Some scholars say BDSM is ok but I want to make sure.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu`alayhi wa sallam, is His slave and Messenger.

The mentioned sexual practices are contrary to the sound human disposition and are forms of sexual perversion and sex sanctification.

What further indicates the ugliness of these practices is the unacceptable acts mentioned in this question like bowing to a person as an expression of sexual gratification. It is not permissible to bow to a created being as per the Sharee‘ah because bowing is an act of worship that must be devoted exclusively to Allah, The Exalted. The Sharee‘ah forbids bowing to other than Allah, The Exalted, even while greeting others. Bowing as an expression of sexual gratification is impermissible for a greater reason. Anas ibn Malik, may Allah be pleased with him, narrated that a man said: “O Messenger of Allah! When a man among us meets his brother or his friend should he bow to him?” He said: “No.” The man continued: “Should he embrace him and kiss him?” He said: “No.” He said: “Should he take his hand and shake it?” He said: “Yes.” [At-Tirmithi]

Ibn Taymiyyah said: “According to the Sharee‘ah, it is only permissible to prostrate oneself before Allah, The Exalted. It is even prohibited to stand for others as a gesture of respect like non-Muslims do; how about bowing and prostrating to others? Bowing the head to others is also prohibited.”

Bowing to others is prohibited as underlined above, however, it does not amount to Kufr (disbelief) unless the doer intends to venerate the created being in a similar way he venerates the Creator. In this case, the doer would be considered out of the fold of Islam. The Shafi‘i scholar Al-Bujayrimi said: “Bowing to a created being like some people do when greeting great people is absolutely prohibited and the same goes for intending to venerate them even if the doer does not intend to venerate them in a similar way he venerates Allah, The Exalted. If he intends to venerate them in a similar way he venerates Allah, The Exalted, it is considered as an act of Kufr.”

Whoever is plagued with any of these practices, has to hasten to sincere repentance, resolve never to do so again, and strive to avoid them. When Allah, The Exalted, sees a person’s sincerity, He blesses him with success. Allah, The Exalted, Says (what means): {Obedience and good words. And when the matter [of fighting] was determined, if they had been true to Allah, it would have been better for them.} [Quran 47:21] He also Says (what means): {And those who strive for Us - We will surely guide them to Our ways. And indeed, Allah is with the doers of good.} [Quran 29:69]

Among the helpful ways to overcome this problem are: remembering the greatness of Allah, The Exalted, the fear of His punishment, and considering the bad consequences of those who continue to engage in these practices, and that they would not be safe from falling into Kufr.
With regard to your statement: “Some people of knowledge say that the BDSM practices are not forbidden.” We do not know of those to whom you are referring, and we do not know of any trustworthy scholar who held that these practices are permissible.

Allah knows best.