How to tell ur bff and not hurt her.?

I already asked a question it is just me and him was hanging out one day and he wraped his arms around ma and kissed me and i kissed him back i really liked it and so did he and we r going to make out soom how do i not hurt her by teller her that i kissed him..... u can email me at kyleehoward11@yahoo.com to help me out on wat to do thanks