I'm not sure why posters think that those who find this poem somewhat problematic are easily offended or 'looking for offence'.
It doesn't offend me, at all. I find the language used, written my a man, relating to a young adolescent female troubling. Particularly the word knickers. Pants would have been a better word, it's much more neutral (yes, and I know, before a million people tell me, knickers is a perfectly neutral term for women's underwear), but, in this context it does feel really prurient, the way language is used is really important and this just feels a bit 'off'.
I understand that many posters don't agree with me, and I'm absolutely of the belief that there should be no shame attached to perfectly normal bodily processes, I'm very open with my own children, we discuss everything, they come to me with many 'embarrassing' teen problems.
And of course I think that men can seek to have understanding about the female experience, and that open discourse is to be encouraged.
I think all of these things.
I also think the the language of that poem, as written by a man, is extremely questionable.
Are posters really saying that they wouldn't raise an eyebrow if a female poet wrote a poem about her adolescent son referencing 'the first semen stains on your briefs'?