What is pentatonic scale?

On a pentatonic scale for guitar, does it matter what I do with my thumb?

• I'm using this position: tab: e-------------------------------------… A-------------------------------------… D------------------------------2------… G------------------2----5-------------… B--------3---5------------------------… E---5---------------------------------… finger position: (1= index, 2- middle 3 =ring 4=pinkie) e-------------------------------------… A-------------------------------------… D------------------------------1------… G-------------------1--4--------------… B--------1---4------------------------… E---3---------------------------------… I can play it with my thumb hanging over the top of the neck, wrapped around like its meant to be most of the time, but it makes the notes on the middle 2 strings, D & G, less clear, I can't leave my finger on the first note on the string, I have to take it off to play the next, my teachers always saying to keep my finger on so that the sound is continuous but also to keep my thumb over, so which should I do? hes said ill need the thumb to do stuff later but i dunno what that is.

• Answer:

  ite m8, soz to get ur hopes up that u got a real answer (I DO THAT ALOT ASWELL LOL) but im just thanking you again for ur top answer lool mesage me if u need a favour lol i dont know a thing about guitars lol but im thinking of gettin an elecho one (electric guitar...thought elecho sounded better lool) cause they sound better in my opinion anywyas speak soon safe.