Myrna Bookbottom was my fave character, not just for her funny moments, but because I like the way her plane(s) look. In particular, her 'normal' plane is modeled on an Avro Lancaster, which is awesome.
Well, from experience, with two people in one body the two sides don't feel what happens to the other. In her case since the shift is caused by emotional response then switches to Miss Basher. Therefore she would switch at the peak of that experience and Myrna would only be there for the first half. Now since the brothers have one set of genitals then they would be counted as one. In conclusion it would be known as a rare 2.5-some. And now you know (and knowing is half the battle.)
Anytime boy, anytime. Helps clear the air, pay the bills if you know what I'm saying. I got a little device I'm working to build. Don't quite have the cash to get to gettin' if you know what I'm saying, wink, wink nudge, nudge. That and I got to get a new barrel for the ol' BSGP. That's the trouble with some of these toons. You put a gun in their face and they go breakin' it in half. Bloody hell it is, now am I right or am I right? Anyway, nice chattin' with ya. Cheerio for now my good sir.