Help me out with caulk

[Slick17601]

Bill J. makes a great point- some masking or painters tape makes the task much easier also.

 

[1sttruck]

I'd use a %100 silicone as it has good adhesions and flexibility. I used an acrylic latex on the outside of the house as that's what was recommended at the time, spent over a week running up and down ladder, and all of the joints now have a layer of mold on them.