请问cup one's hands against the windows究竟什么动作

你在窥视屋子内的情况时可以做这个动作，有点把手像望远镜用

如：
Finally, I throw the butt away and cross the line. Stepping over the tape, I creep up to the porch, cup my hands against the window. It's too dark to see in, and my breath steams up the glass. I can only imagine the scene.