Tom Fromm writes:
35. BOX THE GNAT: Starting formation -facing dancers (man and lady). Dancers step forward, join and then raise their right hands. The lady steps forward and does a left-face U turn back under the raised joined hands, as the man walks forward and around the lady while doing a right-face U turn back. Dancers end facing each other, each in the other's starting position.

STYLING: Start with a handshake position. The joined fingers must be held so that the man's fingers may turn over the lady's fingers easily while still providing some degree of security or stabilization. At the completion of the movement, the hands should be in handshake position.

TIMING: 4 steps from point of contact.

When I get ready to teach this move, I will get them into "normal" facing lines. I will tell them we are going to learn a new move, and that it is always done with the person directly in front of you. It will always be done with a dancer of the opposite sex. I tell them that if they look at the feet of the dancer they are looking at, this is where their feet will be at the end of the move.

Now I will have them step toward each other, and take a right handshake hold. I will tell them to not hold very tight, because their hands will need to slide in one another's. At this point, I will have them make an arch. I will stop them momentarily, to tell them what I want them to do next. I will tell them that each is going to walk forward, the girl is going to walk under that arch, while the boy will be walking around the girl. I will tell them that as they pass, they will do a U-Turn Back. I will tell the girls to turn to the left, and the boys to the right. I will again caution them to use loose hand holds, this way no body gets hurt if someone turns the wrong way.

I will walk them through one, then have them do a Do Sa Do. Then I will have them do another while I "cue" it to them, or walk it again. Then I will get them back home and read the definition to them. Then I will have them all do a half sashay, and have two couples at a time do a Box The Gnat, then after a pause, do a right and left thru. I do this, so they can see the action.

I will make a point to NOT always call right and left through after Box The Gnat. Some times, I like to call Box The Gnat, then have them "face" boys right and girls left. It may be over-flow, but if I don't do it a lot, it seems to be OK.