Hi and welcome to knitting help. This is an ongoing thread about an individual who's teaching knitting to her students at school. So you may get more response in a new thread.
But to answer your question -- leave the stitch on the left needle, bring the yarn to the front and purl into the same stitch, move the yarn to the back and knit into it again. That does give you 3 new stitches instead of one.
sue- knitting heretic