I use a technique I call TOB "transference of burden", basically when I borrow anyone money, I ask them to set a date for when they will pay me back. I don't care if it's tomorrow or next year. Then I say, "Okay, boss, I trust you".
Simply you get the person to take responsibility and put trust above the money.
Works everytime, worse case scenario is the person calling and telling you that they can't pay you now, but set another date. They always call.
Go up to the cat and say "I was expecting that dough last week. It's cool, when do you think you can pay me"
P.S All in all, nothing beats good judgement