I guess women can be sexual and spiritual simultaneously but for
men it might be much more difficult, if we are to believe
Patañjali, because, according to yoga-suutras the conditio
sine qua non of samaadhi is "shraddhaa-*viirya*-smRti-samaadhi-
prajñaa, at least for "ordinary" people, and '*viirya*-laabha'
is through brahma-carya. Sperm prolly contains something
that promotes some neurotransmitters (soma?) or stuff, necessary
for "strong" samaadhi. :/
But then again, perhaps 'viirya' in the latter suutra refers
to something else than in the former...
And furthermore, Indra is in one suukta of Rgveda called
'kapRt' (in Finnish: kyrpä [kuerpae]), which word in another suukta
obviously refers to penis. :D