Well it depends. I'm not sure if it feels like using a tampon. It's different.
All I can say is: relax.
When you are nervous you tense up all those muscles which will cause pain when he tries to get inside you, my first time with my boyfriend did not hurt one bit, we both were relaxed and ready.
It felt stronger than a tampon but good, not painful at all.
If the guy your with is a virgin as well, he most likely won't last that long which is good for you.
make him go slow and tell him not to go at it like a wild animal and do it rough cause it will only last a little and it will hurt you so no one wins.