He is 11yo and has his ups and downs, but is generally starting to mature as one would expect for a Yr7 student.
However, one aspect of childish behaviour is still present and if anything is getting worse; he really acts up when we are either about to leave or arrive somewhere. By act up I mean giggling hysterically, doing stupid things to bother his younger brother and just not listening when being told clearly and explicitly to STOP or remove himself from the situation.
WTF is this and how can we stop him doing it? It's beyond fucking annoying. FWIW, his 10yo brother (who is autistic) doesn't do this.