Let's say a person helps you study for an exam (as a favor). What is the activity/verb that describes that person when he keeps re-mentioning it, as to make you feel that you owe him something.
Is there a one-word verb (or adjective) for it?
person1: Can you give me a ride to the airport?
person2: Sorry, I'm busy.
person1: But I helped you study for your exam last week.
person2: Ok, I'll give you a ride.
person1: Hey, I need some cash. You don't mind giving me some, since I helped you pass that exam two weeks ago.
person2: Ok, stop being such a (the word I'm looking for).
I believe many words could be used in this scenario, such as abusive or manipulative. However, I am looking for a more exact work, which describes the action of constant referencing of a previous favor, to make the other feel obligated to help.