Was sultry the word you intended to use? In addition to meaning warm or stuffy, it can also have connotations of being sexually seductive.

HisRotundity said:

Was sultry the word you intended to use? In addition to meaning warm or stuffy, it can also have connotations of being sexually seductive.

I intended to use "sultry" as "hot with humid, and uncomfortable" but had no intention of sexual meaning. I thought this word is better than hot or warm because it can emphasize Oku's hugging is uncomfortable for Remilia.
If this word makes misunderstandings, I'll change it to another word.

When describing the air or weather, sultry means hot or humid. When describing a person, especially a woman, sultry means "attractive in a way that suggests a passionate nature."

HisRotundity said:

When describing the air or weather, sultry means hot or humid. When describing a person, especially a woman, sultry means "attractive in a way that suggests a passionate nature."

Thank you for your detailed advice. To avoid those meanings, I chose "sticky". I think this would match with sentences.