Marko Metzinger/Studio D

...the nice guy-nice, but not your type-who asks you on a date: 

1 "I'm sorry, I can't." If you're feeling weak, you can add, "I'm seeing someone." If you have no spine whatsoever, you can start with "I'm very flattered, but..."

...your partner, who's suggesting a far-out sexual act: 

2 Look appalled and shriek, "What is wrong with you?!" Just kidding. Spare your partner your horror, says relationship expert Logan Levkoff, author of Third Base Ain't What It Used to Be. It's enough to say, "I understand why you're curious, but it's not something I'm ready to do right now."

...a partner's sexual performance that feels all wrong:

3 Say nothing, Levkoff advises. Move your partner's hand or your own body to signal the change in action that you'd prefer.

...sex, period: 

4 Use the same body language and tone of voice you'd use if you were saying yes, says sex therapist Joy Davidson, PhD. Instead of immediately shooing away his bedroom advances or wriggling out of his come-up-behind-you-in-the-kitchen embrace, "enjoy it for five seconds," Davidson says. Then give your version of an Mmm, that's so nice before explaining your reason for not going any further ("I have a deadline..." or "I'm so exhausted tonight..." or "Damn! I've got 30 seconds to get out the door...").

Penny Wrenn is a New York-based freelance writer whose work has appeared in Esquire, Essence, and Redbook.