Ds1 is just 11, in Year 6 at school. He is a relatively bright boy (relevant because he gets teased for being a know-all). He is happy in his own skin, which I think can be difficult to carry at that age. So, he belongs to Book Club even though no other boys do & Scouts even though he's the only one on his class. He's not afraid to be different & never has been. I know this will stand him in good stead later in life, but it doesn't always work well at primary school.
He has always said that he doesn't feel like he is part of any 'group' at school. He is always allowed to play with any group, but as a hanger-on rather than a group member. He is friends with girls as well as boys. He often has friends round to play, meets up with friends on his bike, brings them on days out etc.
Today, he came home saying that 2 boys he counted as friends were mean to him today. Asking him if he is gay/straight/bent & he didn't know what all that meant. Somebody explained to him afterwards. They were also saying things at the lunch table & others were laughing, all except 2 boys.
I have advised him to ignore them as much as possible but not be mean & to hang around with others who are nice & not part of groups. I will encourage him to ask them round here. But beyond that, I don't know what to do 
I was also very different & independent as a child & never part of any group, but instead had a few good friends, still am now in fact. It is difficult sometimes & so easy to feel left out I don't want him to grow up feeling the same way I did, rejected by my peers, but I honestly don't know what to do!
Any advice would be gratefully received!