No means no, yes means hell yes.
This was sex ed, back in my day (yes, I'm old) :
As a side note, The Walrus is an absolutely fantastic magazine. I follow them online everywhere and have a subscription. It's a great intersection of culture, art, and politics, mostly focused on Canada, but of course, you know it's a good publication because what they write is just as relevant here in the US.
Man, sex ed has changed since I last at a class (probably 10 years ago). We just went into STD prevention and stuff, and we had the most minimalist of genital diagrams; they totally messed up what I thought vaginas looked like. Turns out they aren't like the intersection of a venn diagram with asterisks at 'important' parts.
I only remember the teacher demonstrating how to put a condom on with a cucumber, and saying something along the lines of "remember, always use a condom so your penis won't end up looking like this."
I shoplifted a box of condoms that very day.
True story: the first and only sex ed class I ever had was my senior year of high school. (This was due to a variety of factors and not the norm in my school district, fwiw. I was also already sexually active at that point - but, due to friends taking sex ed classes and Planned Parenthood, also aware of STD dangers, etc.)