My 21 month old has officially hit the terrible two's and has started hitting. Whenever he hits his 4yr old sister, I usually pop his hand and then put him in his crib until he calms down. However, his sister has started hitting back and I think she needs a more severe correction since she is older. I don't know what the appropriate method of discipline is for each of them because I don't want her to think that her punishment is more harsh than his. How do I implement fair and effective discipline, for the same offense, for children that are different ages?