This requires basic Ki control and a lot of concentration.
Picture yourself, in whatever position you think most feasable. It must be you and not what you wish to look like.
Picture heat as black to blue to red to white, a typical colour scale. Now picture the colours changing. Red turning to Blue and so forth. The basic rules of Physics apply, energy cannot be created/destroyed, so no making or destroying the heat, just move it to where you want it to be.
This is useful in the cold and I can say from experience that it works, because I've was out on the coldest recorded day in britain a few years back and this really helped. If you picture your surroundings and you have enough concentration and Ki you can change that too.