Check out the video tutorial below and learn how to decrease with the single crochet two together (sc2tog).
The single crochet two together is a way of decreasing your work by joining to stitches of the previous round or row with a single crochet. It helps to shape your work by decreasing the number of stitches of the round or row you are working.
I like to use the single crochet two together in flat pieces because I feel it shapes them in a more define way, and because the back is smooth, it doesn't leave clear markings like with the invisible decrease.
Hope it helps! Suggestions for future videos and comments are always welcome! =D