I’ve yet to actually need to resort to that, my primary and standby powerbanks would have to run out first 
Just testing it out now with a type-C PD tester, using a proper type-C cable, even in momentary mode my phone will just end up charging the light, at 1.6A at that 
so yeah apparently an OTG->type A->type C contraption is needed. With that my phone is taking 6W in, not stellar but will get you out of a pickle.
Oh and getting out of momentary takes fully removing the head as threads are sporadically conductive, PITA.