If you are really big, you may want to try a female condom, an FC2. The reason is that to the guy it feels like he is bareback. To the female there is absolutely no rubbing that can make sore spots in her vagina, sometimes a problem with large cocks and/or long sex sessions. Yes, it is more expensive, but you can leave it in all evening and have sloppy seconds in it.
It is a large condom made of nytril (tough and good for people with latex allergy). It is placed in the vagina so that the ring at the bottom of the condom is deep inside her and the ring at the top of the condom is outside her pussy. We add some lube inside the condom so that it will always be slick to the guy. We like to put it in before the sex play starts. That way there is no interruption and the inside of the condom feels hot and wet when the guy's cock goes in.
My GF likes to hold the outer ring with her fingers as the guy puts his cock in just to make sure his cock goes inside the condom, and the outer ring stays outside her pussy.
The only thing to be cautioned about is that the guy should not pull his cock out and rub it on her clit. That will result in his cock head catching the outer ring of the condom and pulling the condom out of her pussy. That can be fixed several ways, either the gal can put the condom back in, or the guy can pull the condom onto his cock and put both in her pussy at the same time.
Suggest you try some. And when you do, give some feedback here so others can see how it works for you.