I had the chance to speak about this with my T today, which was awfully nice. She didn't say yes or no, just that she thought it was I good idea if I thought it was a good idea.
I'm pretty determined to move forward! I'm thinking about taking steps though. Like maybe purchase some, well, lube first and see how I feel keeping that around. If I'm still OK with it after a little while, then it'll be on to the toy itself.
And if I do get into one of my modes of self-hatred and guilt over it, I'm going to take the advice I was given here and wait at least one week before doing anything about it. In that time, I can come here and vent.

I must sound like a broken record now, but thanks again to all who've taken the time to reply, it makes a world of difference for me.