From what I remember, pretty casual. I was real young when I first heard about boners on a ytp video, but I don't think my mom explained what it was because I was too young. Otherwise, it was chill on the sex front. Got a talk from my dad for some reason on a 2 person paddle boat on a lake. Otherwise, that's all I can remember of my parents talking sex ed to me, which is fine since I am a pretty safe sex positive person despite never doing it with anything but my hand.
As for drugs, also pretty relaxed. My parents wouldn't wanna see us doing any hardcore drugs but are fine with drugs in most situations. Exception being things like when doctors wanted to give an adult dose of addictive pain killers to my older brother who was pre-teen at the time. They would also rather we do drugs at home in case something happens. Same thing with drinking. They're also okay with weed, but I am the only person in the immediate family who doesn't do it ar all ( health reasons ).
Same rules applied to alcohol, but I never really drank until legal age because I was more boring as a teen than I currently am.