My father died when I was 11, so I never got the chance to "party" with him. He'd given up drinking when I was born but in the last year or so of his life he'd gotten back into it on occasion. Stole my first cigarette from my old man when I was 10, started smoking regularly after he died a year later.
My mom was never a fan of drinking/smoking weed, but would do so on occasion. I started "partying" around 12, first by stealing shots from a bottle of gin my mom had hid under the sink, then a year or so later a few friends from school and I would find ways to get alcohol, usually someone's older brother or stepdad, and usually drink in the woods or at my one friends house whose parents didn't give a fuck. They didn't smoke/drink, but they didn't care either. Was in the projects, so take that for what it's worth.
I remember smoking weed with several of my friends parents as well as my own mother a couple times, but that was after I'd started smoking it regularly and she knew I did it. Most adults were more hesitant to buy/give us alcohol than to smoke/sell weed to us honestly, so at least where i'm at getting weed was way easier than alcohol when I was underage. Everywhere carded for alcohol, but I could buy my own cigarettes from the time I was 15.
My mom would let me have friends over and we'd party in my room, but usually it wasn't drinking it was weed. Can't recall having any drinking parties at my house in high school with my mom's permission, although there were many times when she wasn't home that I did invite people over to drink. My mom had the attitude of "You're a teenager, you're going to do whatever you want regardless if I try and stop you, I can't watch you 24/7" and basically let me do whatever I wanted. Never bummed money off my mom either, always had money saved up from mowing, raking leaves, etc. etc. I was often the one to "provide" the party, at least with some friends, they'd provide the place and I'd provide the booze (i.e. they were broke and I couldn't have drinking parties at home with my mom home).
So I personally was allowed to party and basically do what I wanted in the house (mom wouldn't buy me alcohol, either) but I wasn't allowed to have kids drinking there (at least while she was home...) but had many parties blazing it up in my bedroom.
I snuck a few girls during high school and fingered/fucked them on the couch while my mom and brother were asleep upstairs (shared a room...) but they were just pieces of ass, not girls I was dating. We didn't have sex parties, nor did my mom "set me up" with any girls. Would've been awkward as fuck with my mom in the house... Luckily I started driving the day I turned 16 and had a truck so getting out of the house wasn't difficult.