Help! Breastfeeding 4 month old twins

Li

My twins are 4 months old (3 months adjusted) and have really started to interact, which is adorable and amazing. They can just lay together and smile and coo at each other 😆😍 However, just the past week or so while they're tandem nursing, they lock eyes and smile and coo and end up unlatching and then kind of biting me and it freakin hurts! Any tips?? I tried rolling up a burp cloth and sticking it between them but they can still hear each other.

And here's what they do while nursing 🙄 (my boobs aren't really that lopsided, my daughter just smooshed her face in there).