Ingwaz is a Rune of masculine fertility and gestation in terms of things waiting to come to full fruition as the seed waits in the soil for the appropriate conditions for growth. There is also the concept of sacrifice (as the sun god is sacrificed at the autumn equinox to return with the spring), or as the end of the seed is the birth of the plant, and the abundance of plenty.
There are two ways to draw Ingwaz, one as a simple square of containment and the other as two X’s stacked one upon the other. The latter symbol suggests two Gifu runes, symbols of giving and receiving, implying that with Ingwaz there is a dual exchange. Ingwaz is a Rune of the divine twins Freyr and Freyja, the Vanir twins, who were their selves thought to have been conceived by another pair of twins, Njördr and Nerthus. In some ancient cultures marriage between brother and sister was socially acceptable.
The intimacy between twins suggests to me of the divine hermaphrodite; I claim responsibility for this interpretation. My reasoning is that the Vanir gods and goddesses were credited for their special magical gifts and abilities that come from higher mind. I believe the divine hermaphrodite represents the sacred marriage in which the male and female aspects of an individual human being (either man or woman) are fully actualized and operational. Man is incomplete without woman and woman is incomplete without man: the polarities of male (active polarity) and female (receptive/passive polarity) combine to form the higher mind in an enlightened person, regardless of their physical sexual orientation.
Another thought I had was that the two X’s of Ingwaz might stand for both the gift (Gifu) and the need (Nauthiz). Nauthiz offers the gift of itself in revealing the action that must to be taken to escape the difficulty it presents, as the enclosure of Ingwaz contains the seed in the soil until the proper time for its growth. The gift and the need accompany one another.
 Freya Aswyn, Northern Mysteries & Magic, p. 80