It is recommended that you remove your tampon before you have sex. Having sex with a tampon in might push the tampon up farther in the vagina. It could also cause a lot of irritation in your vagina and be especially painful for you. There is a myth that having sex with a tampon in could prevent pregnancy – again, just a myth.  It won’t.

Having sex with a tampon in is not a good idea! There isn’t enough space in your vagina for both a penis and a tampon. Sexual activity could incur some serious discomfort and irritation, so I would recommend you take it out. If you’re worried about making a mess, try a towel or move to the shower.

I definitely wouldn't recommend it! That would be pretty uncomfortable. The place where the guy's penis goes when you have sex is where your tampon goes also. So even though your vagina probably could stretch enough to fit both – after all, it stretches enough for a baby to fit through – it probably wouldn't be the most pleasurable or comfortable experience. As long as you're having safe sex, it's fine to take out your tampon before you do the deed. You can just put a towel or something similar underneath you in case of any drips.