Stretching advice?

Posted in BDSMAdvice and was directed here!

My husband/owner and I were playing around with double stuffing me (his cock and a soft dildo in one hole at the same time) and it caused some vaginal tearing. He's beside himself and is bringing me Advil and ice packs and chocolate and I'm snuggling him to try and keep him from spiraling too hard.

But also, I wanna try again. Because I'm Type A like that.

Does anyone have any toys or methods or advice for how to properly stretch me so that it doesn't happen again, once I'm healed? We used plenty of lube and took it slow but it wasn't enough and I'm worried that if we try again and it doesn't work he'll wrap me in cotton balls and won't rough fuck me for a month. One caveat-- we're not looking to stretch me out permanently, just to make it possible to take a double-stuffing in the moment.