bf wants to try oral with my tampon in?

My ldr boyfriend is coming in a few days, but my period will most likely arrive the day before he comes. He says he really wants to do every thing with me because it's been so long since we've seen each other and suggested I wear a tampon so that he can give me oral. Has anyone ever tried doing this before? If so, what were your experiences? It makes me so embarrassed just thinking about it!