When a word with a sense that has a 下品 qualifier comes up in the “Sentence word marker” widget on the dashboard, it displays as a link labelled “(Reveal definition)”. It's unlikely ever needed, but clicking it selects it as the definition used in a sentence and proceeds to the next one in addition to revealing its text. This is, of course, confusing and should require a second click.
I think it should need some kind of "submit choice" button, which will also reduce anxiety over potential misclicks, as you can see what you've selected before sending.
I don't tag as much as I should so it took a while ;)
But here it is (Sentence word marker widget on the website's dashboard; desktop Chromium browser):
Clicking on the blue link that says “(Reveal definition)” results in the following:
That is, two actions are performed with a single click — revealing the hidden definition and tagging the word in the sentence with that definition. (Afterwards I rectified the wrong choice by searching the sentence in the dictionary and clicking the 🗨 icon.)
Ok - I've adjusted it so that it will not hide those definitions in this particular panel of renshuu, since being able to see all the definitions is requisite for using the tool.