In this cold weather my mugs are really cold to the touch so during this time of year I do warm my mugs.
If I have my large press in use I just sit them under that for 5 mins to warm the bases.
otherwise I pour in an inch of hot water from the kettle leave it for 20 seconds then pour the water into the next mug and so on.
(the mug only needs to be warm not hot)
Then I dry the mugs completely and apply the design ready for pressing.