Objective: How to curb your dog?

Which of the following solutions is more sound in terms of naive physics reasoning?

OPTIONS:
[I] Before the dog defecates, wear the plastic bag like a glove. Pick up the feces up and throw into a proper receptacle.
[II] After the dog defecates, wear the plastic bag like a glove. Pick the feces up and throw into a proper receptacle.
[II]