How to caulk baseboards with no room for a caulking gun

What people tried

Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.

1. 1
   Using expanding foam with a tube
2. 2
   Drilling a small hole in the baseboard to inject foam into the stud cavity
3. 3
   Using post-setting foam poured between studs from above
4. 4
   Using shoe molding or quarter round instead of caulk at the baseboard bottom.

In their words

Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.