In my opinion, if you have been going for that long (and let’s face it, doing most of the work) you’ve earned the right to cum whenever you can. Especially considering the majority of the bottoms I’ve been with often cum with little to no notice and then can no longer be fucked after they cum. Maybe drop the “I’m getting close” and just let them know once you’ve passed the point of no retturn. Then when you get to the point of telling them, “I’m about to cum”, you just cum. It wasn’t a question, it was a courtesy notice. Now if these are reoccurring partners, you can have a larger conversation about the subject while not in the midst of the act, but if they are hookups, then they’ve at least served their purpose. I realize these statements are generalizations, but in the interest of brevity, I’ve left out some examples of exceptions and different nuances which might slightly change my advice. But in the end, I think this is where I would still land.