Treat it like brushing your teeth rather than like meditating. Nobody is good at brushing their teeth, and nobody skips it because last night's went badly.

A cold shower hands you a clean, timed urge to work with. You plan a minute, and four seconds in every part of you wants out: notice it, breathe, let the wave pass, then notice it come back.

This goes the way learning a bicycle went. You could not, then you could but only with all of your attention, then one day you rode without thinking about it. The middle bit is the ugly bit.

If you held back at four o'clock and then snapped at seven, the holding back still happened. A later slip does not reach backwards and cancel it.