You will love germany and Eurpoe in general. I think it's important for all Americans to visit and see Europe, get a different world view.
Anyway, there is NO over the counter gear in either Germany or Holland. It is available only through prescription. Pins ARE available over the counter in Holland, not sure about Germany.
However, your overseas sources are "domestic" here, so you eliminate the whole US customs and legal structure from your planning.
It is still possible to get gear over the counter in Turkey, I believe discretely in Greece and Spain as an over the counter source has dried up..... need a prescription there now. Our eastern Eurpoean bro's need to respond to availability in the east.
As for other drugs, Amsterdan is amazing. Coffee Shops abound where you can get hash and marijuana. There are other shops where you can purchase psylosybin mushrooms (sp) and herbal estacy, that is not bad. The real E is easy to find and about 1/4 the cost in the states (about 6 dollars a piece). I also know of a club where you can purchase balloons of Nitrous Oxide at the bar, just like ordering a beer. A balloon and beer on the dance floor LOL.
Also, there is no longer an American Military presence in Holland. The air base is closed and the nukes gone. I do not believe that the american military police have undercover MPs cruising the hash bars looking for American military personel. There are SOOOOOOOOO many American here that an American English conversation will NOT identify you as a soldier. I think FISH is a bit paranoid.