Rushing in is a way of not being fully there.
One of the instructions for being a yoga teacher is to wash your hands and feet before class. There are sanitary reasons for doing this, as well as purity reasons that come from older belief systems. For me, though, there's a nice metaphor here about taking time before teaching to "wash off" whatever emotional junk a teacher can accumulate throughout the day. Usually before I teach, I try to squeeze in one more thing--another email, another graded quiz, whatever. Lately, I've been trying to do this hand washing practice before going to teach my English classes. There's something nice about taking that moment to collect myself, to let go of other things that may be on my mind, and to generally prepare myself to be fully attentive to my students. To go in clean, as it were.