How to flirt with a guy via Facebook or some other cyber account? Help?

[delailah]

I like this guy that lives in Canada I know him, I know he liked me he was my bros good friend , we became closer the year I was moving , I moved to another country but am planning to visit him this summer hopefully.. I talked with him via Facebook since I moved weve always talked about school his work weather and how were both doing in general nothing so interesting and fun , and lately he hasn't been replying fast.. Idk why .. Any ways my question is how can I flirt with him via fb or say something that will get his attention ..? If yes how?? Please and thank you a lot