The phrase pencil it in or pencil you in is sometimes used jokingly among busy friends in instances like this. See def. 2 From NOAD:
pencil something in 1 fill in an area or shape with pencil strokes : a lot of the outlines had been penciled in. 2 arrange, forecast, or note down something provisionally or tentatively : May 15 was penciled in as the date for the meeting. • (pencil someone in) make a provisional or tentative arrangement with or for someone : he was penciled in for surgery at the end of the month.
Pencil is used because the plan is tentative and pencil can easily be erased. In some circumstances this idiom can be used as a not-so-subtle way of saying the meeting will never happen (i.e. "Sure, I'll pencil that in next week") but among friends who obviously want to get together, it can be a way of gently poking fun at someone's busy schedule while letting them know you really want to get together. You could say:
Sure, let's do it. I'm free Tuesday and Thursday evening. Can you pencil me in?
Re-reading your question, I realized the crux has more to do with what to call the dates and times you can meet. I think the wording of my example works well—just calling them the times that you're free. Of course, if there is some romantic interest, you could also call them the times you are available with a slight emphasis on that word.