When I'm putting my t'fila shel rosh, it starts off before me, and I wish to fit it onto my head so that the knot is behind me, the box (bayis) before me, and the dangling straps before me: that's how it's worn. So I hold the box in one hand, the knot in the other, slip the knot over my head to the nape of my neck, and fit the t'fila onto my head. The box and straps remain before me, and I'm done.
However, I have seen many a person move the knot and dangling straps around his head to one side so the whole thing is behind him, then fit it on. The straps are then behind him, and, after the t'fila is in place, he has to move the straps forward around either side of his body. Is there a reason for doing it this way, either halacha- or minhag-based or practical? (The latter is hard to imagine, as it seems rather impractical.)