Edit
A subset of spread legs where both legs are bent so as to form a V shape over the upper torso. This is most common when a character is on their back or when jumping and kicking both of their legs up for a split second. Note that the knees should be either minimally bent or not at all, so that the full length of the leg forms a V shape, not just the upper legs.
If you can see both upper legs but only one lower leg (post #1508826), do not use this tag since you don't know what the other lower leg is doing.
This tag should not be used for when the character is standing - in this instance, use legs apart.
See also
This tag implicates spread_legs (learn more).
1