Combination of I+S+O

I have 2 friends that we often hang out together. When we walked together, our combination looks like I.S.O. (by the body shape). Hey, 2 of you, you know who is the I and who is the O lah. And I'm of course.... the SSSSSS. Hint: Miss O has just been able to visit Blog page this recently. As for Miss I.... I think god forgot to write any script for her, that's why she is always "......." and "zzzzzzzzz".