When my children have incidences such as this or not following the rules that disrupts the classroom. I have them write notes of apology to the (victim) or person he was disrespectful to. I have a 6 yr old (and older boys), he has to at least apologize for what he did wrong, what he should have done differently to have a different outcome and what he will do in the future. I expect it in letter form-Mrs. so and so, very neat and in the best spelling possible. Actually, I really want to make it last as long as possible, so they remember the offense. I also have the adressee sign and return the envelope to ensure that they did indeed recieve it and to show them that the incident was more than just a "talking to".
They are also grounded for the day, no tv, no goodie snacks (only pretzels), no company, no special time with parents, no electronics etc.