My Guinea Pig Is Shaking?

[Morgaaan.ann]

whenever I take my pig out of his cage and put him down on the bed he sits and shakes. Like a deep vibrating but doesn't make any sounds. I've read multiple meanings but I'm not

 

[sport_billy]

Hello, welcome to the forum. Have you had him long?

 

[Morgaaan.ann]

I've had him for a couple of months now