Sarah asks, "My boyfriend is a really bad kisser. I don't want him to think I'm avoiding kissing him, but... How do I tell him without offending him, or show him how to kiss without really showing him?"
Bonny's answer: You don't say specifically why your boyfriend is a bad kisser, so I have to assume he's doing something that you don't enjoy. Too much tongue perhaps, or maybe he doesn't understand the tempo or rhythm of a great kiss. Either way the fix is fairly straightforward: make a game out of it. Tell your boyfriend you want to try something new, and ask him to follow what you do - a mime if you would. Ask him to close his eyes, open his mouth slightly, and be flexible with whatever comes his way. Then kiss him the way you like to be kissed, teasing him gently if he starts doing his own thing instead of taking your lead. "Nuh uh! This is my version of Simon Says, and Sarah says close your eyes and relax!"
You could also try different methods of kissing to get some new ideas for the both of you to try. Make a night of it even, attempting to mimic the kisses in your favorite movies, or teach each other how to give a 'screen kiss' just in case one of you decides to become a famous actor and, well, you know. Take kissing quizz, make a list of all the different types of kisses there are, or tell him you read about a new kissing technique you'd like to try out. Point is, have fun with it, and be open to learning something new yourself. And when your partner's bad kissing turns into something divine, make sure to moan or otherwise display your pleasure so he knows without question he's on the right track.