Shoulder rubs tend to take a lot of time and if your stats are too low surprise shower visits not only lower their Love but sometimes even make them keep running away from you. The massage puzzle has better returns, but even that can run out the clock before you finish.
Full disclosure: I'm using the Expanded mod (which has a money cheat), so buying cologne is a lot easier.
That being said, if cologne isn't getting used for anything further than temporary boosts maybe either make the option for a smaller cheaper bottle (each cologne has 5-6 uses) or just lower the cologne price.
I'm with the expanded mod as well, and using the corruption cologne every day since I swim in green, too. But for the base game (actually, does the base game has the cologne back as well? I haven't tried) meeting the girls in the shower can have a negative effect on them the first time on their love stat, but it's minimal, or even turns out you get +1 in total if you apologize to them. The increase to inhibition helps you further the relationships significantly, and any meeting after the first one helps even more. Anyway, if we're talking about a one time use, maybe the books, or dating would give you a better return than the cologne? I mean, of course you play however you want, but if you rather be time/money efficient, I think those have better chances of shortening your grind.