Thanks for the info and hrm... I would have thought imagining oneself doing it would almost act as "practice", rather than having the opposite effect. Oh well, and thanks, good info!
Over a longer time scale it might work as practice (just as engaging in self-control seems to build stronger self-control abilities over the long term), but the immediate effect looks like depletion.
Just saw this article on reddit and thought it would be relevant here: Self Control is Contagious, Study Finds
Apparently seeing other people exhibit self control or even just thinking of them tends to increase (or decrease if observing poor self control) one's own self control.