"Kid in 5th grade asked what flavored condoms are for, while trying to stifle his laughter. Teacher responded with "use your best judgment."

– spareanyexchange

Flavored condoms come in a range of flavors, from strawberry to chocolate. It helps cover the normal latex smell and taste during oral sex, and protects you against STI's.

Kid: "Why do people bounce up and down when they have sex?"

Teacher (very casually): "I don't know, I guess they just think it feels better that way."

– SteevIrwin

The bouncing up and down is usually the act of sexual penetration. Best done using a condom, of course. 

 "Can I get pregnant from a dog?"- popular blonde girl, 9th grade

– moshishi

Nope! You can't get pregnant from any type of animal (other than human). Instead, you might be left with an infection. Women are only able to conceive from male sperm. That's it. 

Girl: "Can you get pregnant from having anal?

Teacher: "Um... See me after class."

– DatWhiteGuy

Couples of all kinds often engage in anal sex, but it's physically impossible for a woman to get pregnant via anal sex. This is because women get pregnant when a male sperm fertilizes a female's egg, which happens when a man ejaculates sperm into a woman's vagina.

Guy in 7th grade loudly decried wearing a condom, said he had a better method. He'd put lemon juice on his penis just before sex, and even though it was a terrible sting (for both of them), it killed the sperm and meant he could go raw worry free.

The next year he dropped to take care of his newborn child.

– legendof_chris 

Surprisingly, lemon juice has been a form of contraception for many years. It may have some spermicidal effects, but it will also hurt like hell and severely disrupt the vaginal flora. You're essentially putting acid on your genitals. Don't do it!

The best one I ever heard was: "If I cloned myself, and then had intercourse with my clone, would that be considered sex or masturbation?"

Couldn't stop laughing at that one.

– THE_BANQUET_BEER

It'd be sex, but extremely odd. You would essentially be having sex with your identical twin.

 Those poor sex education teachers.