I worked with a graduate professor at my undergraduate university (which I just graduated from this year) on a couple of projects in my final year. On one of the projects, I worked with him as a paid research assistant. I used the other project as my 4th year research project for course credit (so did not get paid) and that project is being submitted for publication. Although, I was just one member of a team of about 10 people on that project. My supervisor was very nice and helped me out a lot. Actually, on my first contact with him he offered to discuss my future plans with me and offer some advice (which he did and was very helpful).
I had my last contact with him in May via email, just after we finished the second project, when I thanked him for the opportunities he provided me. We exchanged a couple of brief emails back-and-forth, and that was the last time I spoke with him. I have spent the past 6 months trying to figure out what I would like to study in graduate school (I was stuck deciding between 2 programs). Now I believe I know where I want to go and what I want to study.
Earlier this year, my supervisor mentioned that he knows some people at the school I would like to apply to (for this program, I need to contact potential advisors ahead of time). He briefly mentioned some names that I had since forgotten.
I would like to get in contact with my supervisor again and ask:
for the names of the researchers he mentioned; and
to use him as a reference in my applications.
However, since it has been so many months since we've spoken, I am worried that this would be considered "rude" as I am only contacting him to get something from him.
How should I go about contacting him and how should I frame my email as to not sound greedy or selfish?