I guess it’s just because I am really shy, socially awkward and very introverted and withdrawn in general. I don’t have the greatest body and I have to admit while some people can be naked without making a sexual association I would feel incredible sexual tension being naked even casually. Maybe I would get used to it over time, but I have ever had any sexual experiences, so to be naked in front of others would be incredibly intense experience that I am not used to.