The word "suteki" literally means "wonderful," but it sounds a lot like "sexy" and sexy fits with the theme of the song, so I translated it as "sexy" here. I'd just like to note that Sakurai is talking about more than physical sexiness, and in fact, "suteki" doesn't necessarily imply physical beauty–"suteki" is in the eye of the beholder.
The word "tokeru" means "to melt," but also implies sexual wet slipperiness. The word "koko" means "here," but it could refer either to the physical place where the lovers are standing, or a part of the lover's body (in sexual contexts, Japanese speakers commonly use words like "koko" instead of overt words for genitalia).
In this line, Sakurai turned the noun "yume" (dream) into a verb, "yumeru." Note to learners of Japanese: "yumeru" is not actually a verb, except in the Sakurai-verse. I translated it as "fantasy" because "dream" is too closed-mouthed and hard to sing with this melody.
"Sex For You" is the title of a very smutty song on Buck-Tick's fourth album, Taboo. Years later, Sakurai recycled the phrase again in the song "Limbo" on the album Mona Lisa Overdrive. This is the first time he's ever used the phrase "sex for me" in lyrics.
The word "sekirara" means something like "naked with nothing to hide," but since it's spelled with the kanji for "red" plus the kanji for "naked," it seemed appropriate to translate it as "red-handed." The implication in "red-handed" of hands covered in blood goes with the theme of beastliness and ugliness running through the song.
This line literally means "dream within a dream" but I decided that "fantasy in fancy" sounded sexier here, and more sexual. And fancier.