To begin: yes, I've done lots of research into safe cosleeping, my partner and I are both very happy with the whole 'family bed' idea and aren't in much of a rush to get our bedroom to ourselves, I'm getting loads of sleep, the three of us are annoyingly happy, and everything is working great so far. We have a cosleeping cot on the bed too; if I get up in the night I roll the baby into it so he's not swishing about in the bed without me beside him.
My 4 month old has begun wriggling after things that interest him, and presumably will figure out rolling any day now. At the moment, I nurse him down for daytime naps, and then sneak out leaving him conked out in the middle of our king-size bed (duvet and pillows cleared away). Sometimes I tuck him into the cosleeping cot.
The problem is that my mum (generally very supportive of our parenting choices) has expressed serious concern that it's no longer safe for him to nap in the bed 'now he's mobile', and has said she'll give us money so we can buy a cot.
I don't particularly want a full-size cot. I don't have anything against them as such, we just don't have much room (we have an imminent house move in a few months; at the moment if we put it up we'd have to take down the cosleeper to make space, which buggers up bedsharing as I put the baby on that side of me). Given that I nurse him to sleep, which is working fine for us for now, and lifting him the distance required to go down into a cot would wake him up every time... I just don't see how this would work for us. I'd assumed he could just keep sleeping in the big bed.
I offered to get bed rails instead, but she was unconvinced by the safety (yes but the baby could still squeeze between/under them).
Am I just mad? Am I days away from the baby launching himself off the bed in his sleep at any unobserved few minutes? Any other bed sharers out there with any words of wisdom/reassurance?