JNS
I thought a bit more about this....
How about to make such a „stay behind button“ as an „reverse boost button“. So the option to stay behind us limited like the boost. You can do it a several times in the race until it’s „empty“
You could say instead of being faster with the boost, you will slow down with the „stay behind/reverse boost“ same mechanic but opposite effect....
If the devs introduce a "Reverse Boost / Brake" button, at the same time they might want to consider a "Rage Quit" button. Imagine the situation, it's Turkey, you've carefully planned it so that you're in second place on the final lap to take advantage of last lap DRS and just before the DRS zone... Boom! The leader presses his reverse booster button, your driver flies past and then get's re-overtaken with DRS.
At this point you're really going to need the rage quit button! LOL