DMT at higher levels is an undeniably personal experience. I can't speak for lower doses, but I've done DMT with my wife, not simultaneously, and it was administered intravenously with a very small amount of ketamine (4-5 mg) to smooth the transition. Neither of us enjoy smoking/vaporizing, so that option was out. This is the only time I've ever used a needle with her. In retrospect, I'm surprised that she was open and willing.
I can't remember the dose, but it was a breakthrough level. She came back to after about 6-8 minutes, and her first words were, "Thank you." Then she said something that sent chills down my spine. She told me, "It feels like home," which is a thought I'd had before regarding the DMT experience...overwhelming feelings love and belongingness, like dissolving into a warm embrace. The incredible, elaborate visions are only secondary.
Edit: Actually, now that I think of it, we did vaporize DMT together once, about 5-6 years ago. I don't remember too much about it though, and I don't recall that doing it together resulted in any special synergy.