What do you put under your baby's pop up bed?

[TheTeaLady]

I'm thinking that it might be very cold at night for the wee one with just an inbuilt inflatable matress on the ground.
Any thoughts on what to put underneath to keep her toasty and that also won't take up half the car?
Someone on another thread (which i can't find) suggested ikea's sheepskin rug. I love that idea but I think it's too small; the cot's a bit of a giant -- 130cm x 70cm x 65cm. ( www.nscessity.co.uk/Sun-Essentials/Deluxe-UV-Tent-/-Travel-Centre.html )

We put our large NScessity pop up tent on top of a adult size self-inflatable matress. We also draped a light weight adult sleeping bag over the tent, half covering it, to keep the heat in. This kept DS nicely warm over easter.

get a SIM, and it will do for many years.

This weekend DH put DD straight on to the IKEA sheepskin rug on top of the mattress. I have previously put a sheet between DD and the rug because it didn't seem quite right or hygienic (dribble-wise) for her to sleep directly on it but she seemed to love it - slept like a log. No doubt it was really soft and snuggly for her. Now I am going to have to work out how to clean it though.....