Please help- best butt plug for long term wear?

My Master and I have been considering getting me a new butt plug so that at times I could wear it out during the day for work or school. The problem is that I have a butt plug at the moment that is one of the usual ones; wider in the middle and tapered at both ends, with a base at the bottom. There are two issues with it- most bothersome is the fact that it slides out very easily if I am up and walking around, etc. There is no way I could hold it in for even a short period, let alone a day. Secondly, the base at the bottom, even though not overly large, is too big to fit close and comfortably against me- I am quite a small girl and it doesn't stay comfortably between my butt cheeks. It even impedes vaginal sex in the sense that it gets in the way of the cock trying to enter.

Can anyone give me recommendations for a butt plug I could use for long term wear during the day? I'm not looking for something huge, just reasonable. I was thinking perhaps more egg shaped? and/or with something replacing the base like a string or a very thin base with a small circumference? I would love a link to an example as well if possible.

Please please please offer help if you can! I would be very grateful for the assistance. :-)

Tantus Ryder. med (which is really the only size commonly available). Can wear it 10hr no problem. Doesn't rub, doesn't ride up, has a nice tapered end. Not too big, not too small--you'll feel it, but nothing obnoxious. Never "falls out" regardless of whether you have anything holding it in... Tantus makes EXCELLENT quality toys---> silicone, well made, last a long time, worth the price.

Have heard njoy plugs work well too--but they are VERY expensive.

I have no idea what they are called but the beaded butt plugs (3/4" balls on a 5/16" diameter shaft) should stay in and nothing will show. You would probally want to trim it so only one ball remains outside. BTW, these items are one piece, I didn't mean to imply the balls are on a rigid shaft.

I've heard some women say a butt plug gets very uncomfortable after a few hours.

Is it your master's intention to widen your asshole? Or this buttplug task just supposed to keep you mindful of what a slut you are while sitting in class?

If it's the latter then I would recommend something like this. It's a heavy steel ball with holes to put a string through. It slides up one's ass and leaves no external trace, except for the string. The weight and girth of it, however, should definitely do the trick of keeping you focused.