There nothing again westerner game having a thread on the forum - there many in the game under construction forum.
However you'll have to abide by the forums rule, check the pinned messages from Darkfire.
If your game isn't finished you should make the thread in the "Game under construction" forum
check here =>
https://ulmf.org/threads/read-before-posting.12169/
If it's finished the thread goes in the "hentai game" forum
check here =>
https://ulmf.org/threads/read-before-posting.12166/
Also, be mindful that any thread opening must have information about the game (not just "here my blog / patreon...."), no direct linking (like to a demo) or image for game having loli / shota (and for loli, the forum stance is "if it look like loli, then it is loli).
If the informations thread aren't enough or you are unsure, you'd best contact a moderator for detailed informations.