This hissing sound made from pursed lips used to irritate me. Dili ko taxi (I am not a cab), I would tell the one doing it.
I find it rude to be hailed this way. Why not call me by name? Equally rude is finger pressure on the back - the very offensive cousin to the tap on the shoulder, especially if you don't turn immediately and the finger keeps digging into your back.
I had a good friend in college who would do a very exaggerated version of it on my arm or on my thigh even if we were face to face. Miat!, she would say across the library table, as she would scrape her middle finger on my upper arm to get my attention. Ann!, I would respond by digging my middle finger with exaggerated pressure into her arm as well. It never failed to amuse her. She never stopped.