child acts out when I'm with his babysitter

Sometimes when I pick up my child from the babysitter or she drops off and we are both together, he acts horrible.  He never acts like that when we are alone with him.  He is six and has sensory issues and is in therapy and we have seen great improvement in his behavior overall.  Less fits for sure, the fits have dramatically decreased in fact.  The babysitter said most of the time is good with her and has been doing better overall.  Today I went over to her house just for a little while and he and she started to throw grass at each other and then next thing you know, he was pulling her hair. Then she got angry and said she had had enough of it and walked away. I tried to apologize and she said he was "out of control" all the time.  But those are not the reports I have gotten previously.  He has his moments and he's no angel I agree.......   Anyway, the sitter occasionally gets upset and acts like this.   Plus earlier, another child hit her and had to go into the house.

I'm not sure how to deal with this behavior.  I've tried taking away things and spanking, I don't do spanking anymore. I've tried taking away fun things to do.  Nothing seems to work for this issue.  

ONe person suggested we are both authority figures and he is competing with us and since I'm there he picks on her. I just don't know if anyone has ANY suggestions let me know...  

Thanks!

[RockRose]

I think this sitter is weird,  benjimom.  If I had a child in my care who was consistently out of control (which she said) the LAST thing I would do is get into a grass throwing fight with him.    That's just odd.   In a grass throwing fight,  hair pulling seems pretty fair game,  IMHO.  

The fact that another child hit her while you were there,  to me,  indicates she is absolutely not in control.  

Can you find another sitter?

[benjimom]

I don't like the way she acted and walked away like that, I think adults should be able to control themselves better.   He said he pulled her hair b/c she was on him, it all happened so quick. He loves this sitter and she is good with the kids and shows up. I work odd hours and it's not as easy to find a sitter either.  I will see what happens tomorrow.  If she doesn't want to watch anymore, then I will find someone else.  

[boogiesmom07]

does he act bad with u r just mean to her when u r around him? from exsperence of my 3yr old someone that my child has no choice but to see has acted up with this person when i was around but when i wasnt acted like was having a fun time i know this person has hurt my child i have seen it i asked my childs counslor and it was said children feel safe with the parent around so the exspess their feelings at that time
  now that this person hasnt been alone with my child in over a yr attitude has changed an is now a normal child even when seeing this person with me supervising
  im not saying something is happening but talk to ur son instead of getting on to him for acting up maybe something is happening and hes trying to exspress his feelings the best way he knows how

[benjimom]

He does much better when he's alone with each of us, but as soon as we get togther, it's like he gets totally overstimulated.  Gets silly and does a lot of impulsive things.  My son has sensory issues, not sure if it overstimulates or What!