Double Ended Glass Dildo Play

I’ve had a fantasy that I’ve only carried out once but it’s an extremely fun erotic scene to play out. I have a play Dr friend who loves to act out certain scenes. When he wants to play with a couple of guys he will ask if I want to join him and his guy. One situation I took part in involves me and another sub, stripped and go ass to ass with a lubed double ended dildo inserted into us, back to back on all fours. He lubes us up and we gently mate and dock, he then also lubes up our now hard cocks and instructs us firmly to go back and forth. It’s so intense with the added pleasure of us both being stroked and stimulated. I’ve done this only once and it’s so intense leading to the most intense orgasm. As we’ve done this our dominant will go end to end and expect us to take him orally as this perpetuates. I’d love to do it again but have another nude guy at each end to also suck and be instructed and told how to be enjoy the scene. I’d love to know if anyone has done anything similar.