Well, some things might change with other compounds. For instance, your TRT is 125 mg a week. Let's say you add Deca to a cycle at something like 1000mg test and 500 mg Deca.
When you stop, and simply resume 125 mg testosterone, that Deca is going to hang around for another 6-8 weeks. If you are one of the (many) persons who experiences softer erections on test to Deca ratios of 2:1, then it might be advisable to ramp down the testosterone dosage over time rather than all at once resuming 125 mg a week.
If you are not one of those persons, then just resume TRT.
You can also take a break. That is, inject nothing for a month. Then resume TRT.
Many of us who are now lifetime TRT take a break anyway after competitions or anything like that when we have spent some time abusing the body with harsher compounds and higher doses. I do (but not so long that my wife will have anything to complaint about).