Recently my 4 year old has become fascinated in his pen us and constantly has it out his pants. My concern is more about him hiding away to do this and when I walk in he looks embarrassed. I'm not really sure how to deal with thus without making an issue out of it

Through my experience of having 4 children 1 a boy.It is completely normal young children like to explore there gender and can get very silly with it as they dont understand.They wonder what it is and what its for especially if they see that mummy is different.Just try perservere it will pass.Its a stage that they go through.