I'm also in the middle of a commission. Should I suddenly demand a contract? I hopefully will remember the next time around and I have no reason to think there will be issues with this one.

I don't know, I guess I don't really think to ask nor do I feel like I have the right to ask/demand a contract resulting in an inconvenience for one or both of us. I just feel if I ask something like that, I'll lose what work I have. If that makes sense.