Staining inside corner tips?

I know the tip to use a q-tip or makeup applicator to get in the tight inside corners. I'm asking more about tips on not bumping into the adjoining "wall". Like when painting a room, you're supposed to cut in a new wall (wall B) - not getting any paint on the adjoining wall B because you will get a line on the adjoining wall B because you'll have one small line painted before you go back and pain the rest of wall B after wall A.
So if I'm using a rag to stain, any tips on how to get close enough to the edge that is filled in with a q-tip, without getting stain on the adjoining wall. I might be too lazy to tape off the other sides.
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Stain inside corners before assembly.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

And after assembly?
I asssume you'd say to tape the edges before assembly?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Well I no longer stain inside corners after assembly IF I care what it will look like. To keep the stain off of the mating piece use a wide thin straight edge like the one painters use to push into the corner if you don't want to tale and mask off the area. Still you will typically end up darker areas at the joint because you will still have to work that area harder to get the stain into the crack and will never get all of the stain wiped off. I hate staining before and after assembly but not as much as staining inside corners.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Can't be done with a Q-tip and if your are too lazy to tape, you'd probably be too lazy to make a little setup with a foam brush that works.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.