Heated throws are not recommended for use for children under 5 years but we reached out to The Royal Society for the Prevention of Accidents (RoSPA) and they gave the following tips on how to use a heated throw safely:

When testing and selecting the best heated throws we considered size, heat settings, timer function and value. This throw heats up within minutes on the ready to relax mode. If you want to time to switch off within an hour or a few hours that's really straight forwards to do.

Pharmacy product

I'm a size 12 and I can make a human burrito with it. With it being a throw and not a traditional style under sheet electric blanket you place on the mattress you can switch from keeping warm on the sofa to keeping snuggly and warm in bed with great ease.