The straddling position (or astride position) is a spanking position. It is a variant of the over-the-knee position, the frontal over-the-lap position and the tucked-under-the-arm position in which the spankee is astride or straddling the spanker's lap.
The spanker sits in a chair or similar piece of furniture and places the spankee astride one or both knees, along the lap instead of over it. The result is that the spankee "rides" the lap, with their lap usually secured under the spanker's off-arm. The drawing here depicts this position with spanker seated in a crossed-legged posture. This can be quite effective in imobilizing the short or younger spankee.
Another, perhaps more common, variant is to make the spankee straddle only one of the spanker's thighs.
The straddling position, in a way, mimics the way a spankee is positioned over a birching horse. The spread legs make clenching the buttocks difficult; in addition they result in a particularly exposed and helpless, and therefore humiliating position. One disadvantage is that the bottom part of the buttocks (the sweet spot) can be difficult or impossible to spank this way.