Soft Cup while having sex

So ladies, a couple of weeks ago I asked my friend for a tampon for my period and she gave me a soft cup. Haven't used it cause didn't know how it worked, now I still have the soft cup but my SO wants to have sex and I'm on my period. It's really light right now so I ask....has anyone used the soft cup while having sex and if so how did it feel? For him and for you