These answers might change if my other questions get answered, but...
1. I would chose aphrodisiac saliva because your body always adapts to drugs over time, especially if its literally always exposed to them every second of every day. It would be super annoying for a while, but after that, it would just be a fun advantage in the bedroom. It could also have a lot of really interesting applications in terms of social manipulation (if you're that kind of person) considering it would be insanely easy to expose someone to a diluted dose that would just be enough to agitate them if you like spit on your hand before shaking theirs or something like that.
2. This is actually harder. I would say the TiTS world if there was only a ban on transformative ITEMS and I could still develop mutations by interacting with the different creatures in the universe, such as being fucked by a Frostwyrm and transforming into a humanoid version of it, like what happened with Steph Irson. If we're forced to stay in our normal bodies forever, though, I'd have to go with staying in the real world, but I get the GaloMax Pill (ideally 4 of them because I don't want to lose my legs with the 5th dose, although I guess I could make it work with a tight body suit or something if it's required that I experience the full transformation). Being a goo creature that can completely change its shape at will and doesn't need to pay for food or breathe is pretty much just flat out a super power, so I'd definitely go with that as long as it's okay to take 4 doses instead of 5, because it's way easier to explain squishy skin in a real world setting than it would be to explain not having legs. Also, I'm pretty sure this transformation would basically make you invincible to most conventional weapons. I know that's not how the game works because transformations aren't supposed to give gameplay advantages and all that, but you're entirely made of goo and can reshape yourself at will, why would getting stabbed with a knife or shot with a gun do anything to you?
3. I guess I'd take losing two years of my life per orgasm and just do everything in my power to never orgasm while REALLY banking hard on humans inventing a way to transfer our consciousnesses into robotic bodies before I eventually died. If all of these questions were occurring simultaneously, however, I'd pick shrinking because Galotians can add extra mass to their body by ingesting fluids, thus negating the risks of orgasming.