How to backup seed in lightning and give your channel to watchtower this is followup on question #85475: 

I have learned in previous question that there is an automatic refund mechanism in case of force closure of a channel, except for some very rare circumstances. I would like to ask about two of those circumstances:
,

1-how to "back up your channel state" or how to back up your seed in lightning? 
(is "channel state" here a synonym for "seed"?)

And why do people say the "seed" works differently in lightning compared to btc - differently how?
,

2-how can you "give your channel to a watchtower" ?  IN practical terms, if you use a current lightning wallet

thanks
For clightning I have created a video that explains how to restore your node with seed and state you can watch it here: https://youtu.be/-S7pQOw36vI

The general idea is that hsm_secret sites your seed in binary and the sqlite3 datebase sites your channel states. 

I believe in lnd the process would be similar only that they give you the seed words explicitly instead of hsm_secret. They should also have some database or file in which they site channel state. 

As for watchtowers. Currently to the best of my knowledge there are no such services available.