Mom's Bikini.

So we live in mumbai. My mom is 45 years old and she work's in office.She has a good figure and all knows she loves flaunting her navel in saree and like to were short dresses. She were short skirts and dress to.But now I want mom to were bikini in our trip to Andaman island. I dont understand how to say her this . But I want her to were it.She once wore bikini in a goa trip with dad whose pics I have seen in her mobile but she dont were bikini or swimsuit while me and my little brother is there.How I can ask her to were bikini now?