I used to speak with a Russian speaker and she used to repeat something 3 times after she said something bad, it sounded like "steraï steraï steraï". If you see what I'm talking about, can you help me writing it in Russian ? Thanks a lot.
It could be "стирай" indeed. All people are different and have their own, so to speak, traditions. Some people say "тьфу-тьфу-тьфу", some people prefer to use the phrase "типун мне на язык", maybe she likes to say "стирай" when she wants to "erase" some bad thoughts and statements so they don't come true.
It could be the superstitional "тьфу-тьфу-тьфу", or even "чур-чур-чур" as in "чур меня", both often accompanied by spitting over one's left shoulder. The first option is more common to encounter, while the second one matches the pronunciation better, but, nevertheless, both have been traditionally aimed at protecting the speaker against unholy forces.