As I said earlier, do a search.
This question is nothing new.
I think everyone here agrees that it can certainly be done, but you are showing a complete disregard for what this person may want, which is fine, since this is a black magick forum and all, so it’s no different than any other love/lust spell.
However, you really need to take time to consider the consequences for both yourself and the person you are targeting. If you read the above linked threads, there are some posts from experienced magicians who have done this, and it didn’t end well.
You are looking to change a fundamental part of their personality, and if you succeed, you will most likely inadvertently change other aspects too. They will no longer be the person they once were. They may also loath and despise you.
You also have to take into consideration that he may retaliate. If this is not something he wants, you will be causing deep psychological trauma; as @Fuego1 said, you are essentially raping his lower self. His Higher Self, if it doesn’t protect him from your spell outright, may attack you and fuck you up (and your Higher Self will most likely let it if there is a lesson to be learned for you) I’m not talking karma or morality here, just simply possible consequences.
There are always unintended consequences in anything we do, magical or mundane, but magical especially, because we can’t see beyond our own narrow desires.
If he has latent homosexual urges, and you succeed in bringing them out, that’s fine and dandy, but, even in this day and age, that can bring horrible consequences. What if his family then disowns him, or he has a falling out with his religion, which has been a big part of his life? What if, after your tryst, everything he believed about himself is called into question, and he commits suicide? Then your “lust spell” inadvertently becomes a curse, and you are just another petty, immature male that can’t stand rejection and so you destroy the one that rejected you (there are a LOT of these types on this forum and others).
If all you want is to get laid, then surely there are easier ways. If you are fine with the possibility of destroying someone just to get your rocks off, then all the power to you. Just accept the consequences and move on.