I recommend a glass plug
Ive tried a couple others but this one is the most comfortable for long term wearing.
I bought a black silocone one once and within an hour it always leads to bowel movements.
P-spot toys aren't that great, the odd shape just doesn't feel good.
The doc johnson pretty ends medium was alright, i wore it to work many years ago. Though the fantasy didn't really live up to the reality. After 4 hours your ass muscles get sore even if there is a thong supporting it in place. The glass one is much better long term, Just don't buy those heart shaped base ones, the awkward shape of the heart hurts your cheeks after an hour of wear. A circular base is ideal.
Also another secret few may know about is stonewall kitchen lotion, It works better than lube. It's cheaper per oz. It doesn't dry up that fast AND it smells nicer than average lube. Usually with Lube you would feel gross after using it and need to spend lots of time wiping it off, But Stonewall kitchen lotion leaves you feeling clean after use.
Ive tried foot lotion once...bad idea that shit stings, but stonewall kitch lemon parsley or grapefruit thyme are perfectly fine for anal use. (not sure about the effects of the lotion being absorbed into the ass but ive gone through at least 5 bottles so its probably safe) It's also a nice white color as most lotions are.
Anyways i found this lotion actually kept me comfortable for 8+ hours at work
Don't let the glass fool you, the round base is a bit bigger than the part just inside. It's this one: http://www.amazon.com/Don-Wand-Glass-Pleasure-Clear/dp/B0019LWKVQ/
I have no wish to lose something inside.
I believe it is this one. They are really nice and pleasant feeling.