I just went down for full out full in anal thrusts on my nubbed dildo doggy style. After 100 I took a break. Then after trying to start again I felt very fucked and couldn't continue after another 15. Looks like that's all I can do on that dildo in one day, although I thought I might do them in one go.
I tried to use the opportunity for my tunnel plug now after, but abandoned the approach. It's still quite bigger.
EDIT: 135 minutes nose shackle completed. 65 minutes left to do.