I run a Mynode at home on my own hardware and it has something called: "lightning terminal" on it. So when I want to "empty" my lightning channels because I stack using lightning. So I constantly need to move to cold storage I just go to the lighting terminal and do a loop out or if I want to top up a channel I do a Loop in. The service is called Loop when I look at the node's status. it's how I balance my channels on that node and it costs a fraction of what a service like boltz costs. Last year I did a loop out of 20 million sats and only paid about 1000 sats on top of the on chain transaction fee. It can even handle looping multiple channels at once.

So that's what I mean when I say loop I first learned about it reading this darthcoin guide
https://darthcoin.substack.com/p/lightning-network-submarine-swaps

and This is I think the loop repository though I have not actually read it
https://github.com/lightninglabs/loop

Hope this helps if there is anything else just let me know