Adapted from a recent online discussion.
You can't control your flirting sister, but you can control you
Q: My older sister flirts with my boyfriend. Not giggly, bouncy flirt, but an attentive flirt, as a friend who witnessed them described it. She leans in, ignores everyone else, and never lets me have two seconds alone with him while she's around. It's a pattern over the years, flirting with guys I either like or am dating, and she does it to our other sisters as well.
It makes me sick to my stomach to watch. Do I avoid her? Talk to her? She gets very angry and defensive at any criticism. I really want it to stop.
Sisters Share Everything?
A: It won't stop. You can speak up and invite her defensive wrath, you can avoid her, you can warn the men in your life, but nothing will change the fact that your sister apparently has insecurities so deep that other considerations (dignity, decency, loyalty) all defer to her need to persuade herself that she's special.
For dealing with it in the future, I suggest a combination approach: Anticipate her antics and set the bar high for being annoyed by them; talk to her when you have a specific example to cite and say you'd appreciate it if she were more aware of the hard feelings she's stirring up; avoid her as much as possible without estranging yourself from family; warn boyfriends that she does this; and, when and only when these four aren't sufficient to keep her from her "leans in, ignores everyone else, and never lets me have two seconds alone with him while she's around" routine, go up to her and quietly say something along the lines of, "It used to bother me that you did this with all of our boyfriends, but now I just think it's sad."
Anonymous: Do you think there is anything the boyfriends can do specifically? The sister's actions can't be changed, but the boyfriends could get up when she leans in, make extra effort to cling to the girlfriend when sister is around, etc.
Carolyn: Certainly the letter-writer can ask her boyfriend to help her mitigate the sister's ill effects. If he's not sure how to handle it, she can suggest that he go out of his way to be inclusive of others in conversations where the sister is involved or excuse himself to talk to someone else or even just say to her, "Would you please scoot back about a foot? You're close-talking me." That'll disabuse of the idea that validation is available through him.
I don't like the extra-"cling" idea, though; too young-adult sitcom.
If you feel uncomfortable saying something, just don't say it
Q: Is it, or is it not, ever okay to reveal a gender preference while pregnant? I'm expecting, and several friends know (because they asked) that I want a boy, though I will be thrilled either way.
Even though all I'm doing is telling the truth, I always feel a little squicky saying it out loud — but is it really so bad?
A: If you feel squicky saying it out loud, then don't say it.
In case you need persuading, imagine being your daughter, and answer people's (bizarro) questions on preference accordingly.