So your saying when you slide it in, it won't automatically "suck" it in right away? You have to wiggle it around in order for it to recognize that it's there so it "sucks" it in?
You should have to put the disk in about 3/4 of the way in before it sucks it in automatically. If you mean that you have to put the disk in at an angle then something is wrong, otherwise it sounds pretty normal to me.
To OP, I re-read your post and finally know what your problem was. My response - No, I don't have a fish around stick the disc in. It's smooth and effortless. You may want to take your MB to the store, and compare it with other display models.
the problem is when i want to put a cd/dvd inside, sometimes seems the drive is closed, and i have to put it smoothly.is it normal?
No, my drive never felt 'closed' when I insert a disc. My drive is HL-DT-ST DVDRW GS21N. If you have the same one, then yours definitely behaves differently than mine.
Having said that, there's no need to panic. You have a year (of warranty) to test it out. If it's really defective, it's an easy task for Apple to swap out the drive.