It means that Hamas has children stand guard around rocket launchers. As far back as a decade ago, when this started becoming more and more common, I saved a video of a Hamas rocket fuse failing, killing the children guarding it. That was quite when I started taking more of an interest in what is going on over there.
The human shields are Gazan citizens - many of which are themselves happy to die "for the resistance" thanks to UNRWA education. This I have been told at least twice by Gazans face to face, and dozens of times online. Yes, I know Gazans and I speak with them online in Arabic. I suffer a lot of abuse, I have a thick skin (I laugh that I'm divorced, you can't insult me more than my ex).
There is no euphemism. These are real people risking their lives - and sometimes loosing - to protect military equipment designed to exterminate Jews. That is not a euphemism either - even the Gazans who work in Israel clearly state that all Gazans would happily kill any Jew. Just a few weeks before the October attacks I was having a conversation, pleasant and civil, and the guy tells me "without your weapons the Arabs would trample you" - I was unsure if he was threatening me. Just a few weeks after that they overran the Kibbutz where I until recently worked, and killed over 10% of the population. That is literal, biblical, decimation.
It should be also noted, and this is extremely well documented, that between 1/3 and 1/5 of all Hamas rockets fall back into the Gaza strip. That is an extraordinarily dense urban area, and all those injuries are blamed on Israel. Culturally, it makes sense for Arab media to report them as "killed in a war with Israel". But Western media then translates and reports that as "killed by Israel".
This is not some conspiracy theory the Arabs status very clearly. I highly suggest that you go through the Arabic Telegram channels. I personally speak Arabic, but if you don't then Telegram has a built-in translation feature anyway. Or go through any other Arab media, it's all over the place.
If you don't want to see children getting hurt, then stop protecting and encouraging Hamas.