Detumescence--The Expression of Joy--The Occasional
Serious Effects of Coitus.

We have seen what the object of detumescence is, and we have briefly
considered the organs and structures which are chiefly concerned in the
process. We have now to inquire what are the actual phenomena which take
place during the act of detumescence.

Detumescence is normally linked closely to tumescence. Tumescence is the
piling on of the fuel; detumescence is the leaping out of the devouring
flame whence is lighted the torch of life to be handed on from generation
to generation. The whole process is double and yet single; it is exactly
analogous to that by which a pile is driven into the earth by the raising
and then the letting go of a heavy weight which falls on to the head of
the pile. In tumescence the organism is slowly wound up and force
accumulated; in the act of detumescence the accumulated force is let go
and by its liberation the sperm-bearing instrument is driven home.
Courtship, as we commonly term the process of tumescence which takes place
when a woman is first sexually approached by a man, is usually a highly
prolonged process. But it is always necessary to remember that every
repetition of the act of coitus, to be normally and effectively carried
out on both sides, demands a similar double process; detumescence must be
preceded by an abbreviated courtship.

This abbreviated courtship by which tumescence is secured or heightened in
the repetition of acts of coitus which have become familiar, is mainly
tactile.[98] Since the part of the man in coitus is more active and that
of the woman more passive, the sexual sensitivity of the skin seems to be
more pronounced in women. There are, moreover, regions of the surface of a
woman's body where contact, when sympathetic, seems specially liable to
arouse erotic excitement. Such erogenous zones are often specially marked
in the breasts, occasionally in the palm of the hand, the nape of the
neck, the lobule of the ear, the little finger; there is, indeed, perhaps
no part of the surface of the body which may not, in some individuals at
some time, become normally an erogenous zone. In hysteria the erotic
excitability of these zones is sometimes very intense. The lips are,
however, without doubt, the most persistently and poignantly sensitive
region of the whole body outside the sphere of the sexual organs
themselves. Hence the significance of the kiss as a preliminary of
detumesce