Re: Is this ok
Your reaction (orgasm) was perfectly normal. Some girls "ejaculate" extra vaginal fluid when they orgasm and some don't (most don't, because they don't produce enough "natural lubrucant").
You should fix something though. I don't know for sure, but I really think that you shouldn't use your sister's vibrator. Unless you clean it very well, this is the most IMPORTANT thing of hers you shouldn't use (you think she hates it when you wear her clothes, what about THIS!). I think you have to be 18 to buy one, but you can certainly get your mom to buy you one. Of course, this can be very embarrassing, so it might be easier to ask your sister if she is 18 or older. Just tell her you saw hers (I wouldn't mention that you used it) and that you want one. She will probably feel alot more open about by then and could buy you one of your own.
Not using her vibrator is important especially if she gets a vaginal infection (you get these regardless of sexual activity sometimes). You certainly don't want to get that from her, or GIVE it to her (maybe?)!
Hope this will clear things up!