Okay guys, need some advice.

My two year old has always listened very well and has always been very gental and kind.

Now that little brother is a little older they have started playing more together. They like to play peek-a-boo and run through the house chasing one another. They like to throw balls together....But now they like to push each other 🙃

Big brother pushes little brother and hunestly, little brother thinks it is funny. At least, until it isn't funny and he gets pushed straight into a book shelf 😐

When I try and explain "gental" or "be nice" they both laugh at me and big brother says "He likes it!!" And goes back to pushing and little brother laughs hysterically. I have tried time out and it does nothing. I try and redirect to other activities like markers/paint. Does nothing. They just get down and start beating each other up again. What the heck do I do?? Little brother has a big goose egg on his head from yesterday's lovely rock em sock em match they had. Hheeelllppp, I'm yelling and they still don't listen and now I'm just filled with mom guilt because I yell all day... tia guys!