Do you mean a person turns you on, but you can’t understand why because you don’t think they are very good looking?
I think that’s entirely possible. Some men (and I’m sure women too) are highly charismatic. If you look at them in the cold, hard, light, they aren’t handsome or pretty, but there is something about them that just gets you hot and bothered. Equally, there are gorgeous looking people that leave you totally cold.
I used to know this guy. He was without doubt, an ugly looking guy (think Lyle Lovett) and yet, he always had a gorgeous, and I do mean stunningly beautiful, woman on his arm. When you met him and he talked to you he was so confident, so sure of himself (without appearing cocky) and he made you feel beautiful and seen. I can quite see why women fell for him. He was my brother’s friend and I think that gave me a natural defense against his charms and no doubt he kept himself in check around me, but I certainly remember him making me feel very special and beautiful when he talked to me. He just had a way.