I've noticed sometimes in polite company or in the company of strangers some people will saying they are going to wash their hands 去洗手 (qù xǐshǒu) instead of going to the toilet 去上厕所 (qù shàng cèsuǒ).
Alternatively, asking for the 洗手间 (xǐshǒujiān) instead of the 厕所 (cèsuǒ).
Is this something that should be copied? Does it matter for guys, is this more feminine to say 洗手?