If male kobolds, dragonborns, and lizardfolks possessed a sheath, genital slit, or anatomical structure similar to that of humans, what would be the sensation experienced during an erection and how sensitive would it be from base to tip?

I'm not sure how many furries are on this site, so in case you don't get much of a response here: the site e621.net is similar to this site, including a forum, and it's geared toward furries/scalies and other anthros. You may get more of a response there. Heck, I wouldn't be surprised if there's already a forum thread there discussing this very thing.

I'd say something like a swelling at first. A pressure while it's inside the slit, and a tingling. The emergence of the penis from the slit would tingle a lot, since there's a lot of blood rushing to it at once and those nerves are coming alive with sensation.

As for actual sensitivity, that's probably up to artistic interpretation. How sensitive are human dicks? That varies from person to person.

Would you be able to provide me with some links?

e621.net/forum_topics is their forum mainpage. You can search forums there, with the searchbar at the top of the page. It's also pretty easy to make an account, if you want to start a forum thread there.

Could you provide me with a list of links?.

Ok so like, I'm prettyyyy sure we're dealing with another bot here guys.

I'm not a bot.