In between can be dangerous if you or your partner moves in sleep..I’d say right next to you with pillows on outside of the bed and just to be safe maybe lining the floor with cushions next to the bed as well..but if you look up the safe sleep 7 it’ll show you the cuddle curl position best for Cosleeping
Inbetween you is the guidance I believe. Please don’t put pillows on the floor and keep it clear if you sleep with baby on the outside of the bed. If they fall off the pillows can be a suffocation risk. Again I’m basing this off guidance rather than personal experience as I have a floor bed but keep the surrounding areas completely clear x
I personally have always kept my son away from his big dad. He roles and uses his hands too much in his sleep. My bed is tightly against the wall so he can’t get trapped and it’s never happened. We have a very small bed frame. My son also sleeps almost uncomfortably close to me lol.
in between so he doesn't fall off the bed or get stuck between the walls. I'd suggest you each have a blanket of your own just to avoid suffocating your baby