What were they on when they were making Achtung Baby then? The whole album seems to be about sex 
That's one of the many reasons that album is awesome; there was an article in (I think) Mother Jones in the late 80s where the interviewer commented that there wasn't a lot of eroticism in U2's songs at that point - s/he specifically used the lyrics of Marvin Gaye's Sexual Healing and Prince's Little Red Corvette as a point of comparison when Bono tried to insist that there was a sexiness to U2's songs as of the Rattle & Hum era.
Compare R&H to AB, and there's a huge difference, although U2 hadn't yet shown us what they had up their sleeves yet.
Re: "I will swallow!" - that's hilarious

How have I not heard that story before?