In the winter we keep our house colder than we do in the summer. As a result, my sheets are always colder than I'd like them to be before I get in them. I sleep in my boxers regardless of the time of year because it's the most comfortable for me, so my body comes in direct contact with the cold covers.
The only thing that has worked for me so far is when I get the sheets out of the dryer and then immediately get in bed, but I can't do this every night because it's a pain to dry and to put them back on the bed.
I would like to avoid the cost of an electric blanket or heated mattress pad. Additionally, I'd like to be able to warm up my bed when I'm camping outside in the cold.
What's a simple way to warm up the sheets before hand so I don't have to experience the cold of the sheets? If at all possible, I'd like to not remove the covers because it's a hassle to put them back on.