http://ja.wikipedia.org/wiki/H
へえ。
H が性的な意味を持つのは日本だけなのね。
Wikipedia で面白いものがあったら、英語版も要確認、と。
H - Wikipedia (英語)
http://en.wikipedia.org/wiki/H
・ In Japanese, H was originally an abbreviation for
"hentai" (pervert). It has come to mean sexual,
as in H games (pornographic computer games) or H suru
(meaning "to have sex"). Through the popularity of anime
(Japanese animation), the old incorrect meaning has
become known to fans in the west. See also Ecchi.
Ecchi の項を見ろ、と？
どれどれ。
Echi - Wikipedia
http://en.wikipedia.org/wiki/Ecchi
Japanese usage
Ecchi as an adjective can be translated as lewd or sexy,
while as a noun it can be translated as sexual intercourse,
e.g. to do ecchi (ecchi wo suru) would mean to have sex.
English usage
In English, the word is often used in the context of
manga and anime.
なるほどねえ。
日本発の言葉だけど広がりそうな気配はあるな。