Strange Sound From PS4 Slim Upper Plastic Cover

I bought my PS4 Slim last year and I started seeing issues on It.1 Month ago I noticed that when I touch the up side from the plastic cover where It says PS4 , It is making a strange sound like crooch crooch and while I am playing Grand Theft Auto V after about an hour It is making this sound by Its own .I do not know what to do now.Please help me.