Nice little tasks, sure fun to read
good work
I like the mix of a bit mean and a bit fun
As you ask about comments, everyone is allowed to do what they want just a warning from someone that gave rl courses about anal play before.
Plugs are formed like they are for a reason, and I would very highly recommend to use a plug for this. Also with times of way over 2 hours possible, although as you chose the point in the book you have control over how long it will be, you may want to reapply lube, unless you are very used to anal play, several time during this.
If you use a random item there are mainly 2 complications to watch out for.
1st you want something with no sharp edges at all. You want to avoid causing wounds or scratches in or around the anus as infections in that area are possible of course and can be complicated and may need a very long time to heal.
2nd is if the object doesn't have a very wide base there is a real risk of it going in all the way, not only increasing the risk of wounds but the real possibility of it getting stuck, this means a trip to the doc and explaining how you "fell on this beer can by pure accident and by a miracle it ended in your ass"... This is a common thing in ER rooms
Have fun but also be safe and buy a plug and lube for anal, the simple ones cost very little