Using 'presume on' can suggest someone is taking unfair advantage of another's generosity or position. He would often presume on our hospitality and stay longer than invited.
Pro Tip 2/3
Emotional Weight
'Presume on' often carries a negative emotional charge, implying inconsiderateness or exploitation. Please don't presume on her good will, as she's already done a lot for you.
Pro Tip 3/3
Social Caution
Be cautious about cultural context; in some cultures, presuming on relationships is particularly frowned upon. In a formal business setting, one must not presume on a colleague's assistance.