For those of us who are not 'bi-'. . . failing to admit that other cockhead through that membrane is not XXX-citing is pur B-S.
It 'IS' erotic and DOES require more control, especially if that 'other' cock is the one doing the stroke.
In most cases only one cock can thrust, . . . people who have done it multiple times among the three, often the men can learn to rotate the thrust between them, - and if a good back and forth, puss and ass rotation gets going, - she will usually start long multiple orgasms until the men shoot.

nothing better than feel a anther cock against yours and fucking the same pussy together

Oh hell yes!!! Not only can I and my wife feel that the two cocks are rubbing through her, I notice out balls slapping against one another. When we both slide out some, I like positioning myself so that our shafts make contact too... Sometimes she will ask us both to fill one hole... THAT is when things get real interesting.

I love dvp and feeling another cock rubbing right against mine with both our heads rubbing together in a tight pussy

I love it too and you definitely feel the other cock cause the wholes are really close ....have fun

Very close. Separated by one thin membrain. During child birth, a lot of women tear that membrain. It has to be closed surgically or shit can get into the cunt. Infections result. Stick a finger in her ass, and your thumb in her cunt and you can feel how thin it is.