For those of you who side carred the cot to your bed, how did you do this safely? I'm keen to try this but worried about gaps etc.
I rearrange furniture in our bedroom so that the cot is butted up to a wall, which is then butted up to the bed. If the non-sidecarred side of the cot is not pushed against anything you risk the cot jiggling away from the bed, creating a gap.
This keeps the bed base and cot base together.
You then have a mattress gap between the bed mattress and the cot mattress. I roll up a towel or blanket for the gap. The benefit of doing this is that it creates a small raised 'bump', which helps divide the space to baby's and yours. Helps for when baby starts shuffling around, but easy enough to scoot baby over when putting back into the cot.
I have also seen on blogs people who cut a piece of foam mattress to exactly fit the gap between cot and bed.
Also, you can get a massive sheet (perhaps sew together two sheets for the size of your bed) and wrap the bed and cot mattresses together. Along with the rolled up towel or foam cut to size, you tuck a sheet in all the way over your bed and over the cot mattress and tuck in at the other side of the cot. This holds everything together. I've never bothered going this far, but have seen it on blogs.
CoffeeTwo - If you have not yet bought a cot and are planning to side-car, I would highly recommend finding a drop-side cot for the sidecar cot. It means that you can take the side off while baby is tiny. Then once baby is rolling you can add the side back on but having it dropped. This creates a low barrier between you and baby and stops a rolling baby from rolling into you, but the dropside means you can still reach over it easily.