Yeah, it's actually a bit of a hassle if you're on mobile since you have to constantly click on someone’s profile just to DM them. There’s no smooth way to switch between the room and DMs like on desktop.
What I usually do as a workaround is use both the IMVU app and the IMVU website at the same time. I stay in the room using the mobile app so I don't get kicked out or lose my spot, and then I use my browser to log into IMVU and handle my DMs there. It’s still not ideal since you're switching between two platforms, but it’s a lot more stable and helps keep the conversation going without interrupting your place in the room.