Jekyll & Hyde

Trying to get to grips with my 3 year olds behaviour. He can be an absolute angel giving out kisses & cuddles and then suddenly lashes out and hits & kicks. Sometimes this is because he is tired or hungry or maybe filled his pull ups but otherwise for no apparent reason. Got to get to grips with this for all our sakes as poor E is losing her hair to her brother's hair pulling and I'm fed up of being hit...