mel- As in it appeared on his back as if someone was writing it and then disappeared.
doc- You know how to put a slight spin on someone's day, don't you?
mel- Welcome to my world.
doc- Is there any way he can come into my office. 'Cause then maybe it would happen again and I could do some...
It's a little difficult to say just from this short dialogue, but I suggest that he means: You know how to throw someone's day slightly out of kilter by introducing something unexpected/unusual.
This might be caused by both her appearance and her story together.
not a teacher