I can't remember my first, I have vague memories of stumbling across Bondage Fairies and seeing short poorly compressed clips ripped from La Blue Girl, but I remember the thing that really got me into hentai was an AMV for Bible Black set to Relax by Frankie Goes to Hollywood.

Slow internet back then so it was just images for me at first, I think. It probably had something to do with the girls from Bleach (these are some of the oldest saved)

>>446 Does that pic even counts as hentai?

Viper GTS, at the time it was the best hentai ova I'd ever seen when I was new to hentai ova's in my early tweens.

>>1090 Barely, back when paheal was more relevant it still had a ton of shit porn flooding it's gallery. Had to wade through a ton of crap to fine good shit. That still is the truth to this day but thankfully tags exist for most booru styled sites like sankaku and others.