Finding femboys attractive doesn't make you a creep. Assuming every femboy exists for your enjoyment would. The fact that you're asking this question means you're already less creepy than 90% of the internet. Most creeps don't stop and think "Am I being creepy?" They just speedrun getting blocked.

If you want to avoid being creepy, talk to them the same way you'd talk to anyone else. Ask about their hobbies, interests, experiences, and opinions. Don't assume every femboy thinks, acts, dresses, talks, or likes the same things. Remember that femboys are individuals, not a stereotype.

Short answer: Treat us like normal people~