How do you say this? (Warning NSFW)

Question

How would you say: "I want a girl to sit on my face" in Japanese?

Would it be something like this: "俺の顔の上に女の子を座りたいだ"?

Answer 1

Your sentence has two mistakes.

• In Japanese, i-adjectives (and i-adjective-like auxiliaries たい/ない) don't need a copula (だ). You should end this sentence with たい alone, without だ. See this.
• 座りたい means "[I] want to sit" because 座る is always intransitive in Japanese. Using を doesn't automatically make it transitive. Instead of plain 座る, you have to use its causative form, 座らせる.

The corrected version is:

俺の顔の上に女の子を座らせたい。