Yea, it would, because it's going to help your bottom get used to have something in it. You also are going to want to slowly increase the plugs in size until they're similar to the penis or dildo you'll be using.
Thanks for the clarification! Don't worry about it, I get that way when I haven't had my energy drinks LOL
I am very sorry if I was vague (I should have had my coffee first). If you leave the plug in longer does it make for an easier time during anal sex?
It may help, like Jessica said, it gets your ass used to having something in it. But it is the stretching of the sphincter's that you want. Most plugs have a smaller neck to them and that is what the ass conforms to. If you can do some small thrusting using the body of the plug that will do better at getting you ready for a penis. You may try a couple different sized dildo's instead, start small and work your way up to the size you need.
As DWTim mentioned you are looking for stretching of the sphincter (don't worry it won't be permanent) and the ability to get your sphincters (both inner and outer) to relax and allow penetration. Slow gentle stretching and some smooth thrusting with plenty of lube will help prepare you for anal sex. Leaving a plug in longer will prepare you if you want to have a penis sit inside you for a while but it doesn't do much for the thrusting of sex. You want a combination of the two some gentle thrusting and some training to accept the penis without pain.