For a warm up i like to do las stretch for 1/2 hour or so then i do basic manual stretches after those i strap in for as long as i can handle the discomfort.
During my rest period i will continue to las stretch until i strap in again.
The swelling you are asking about could be from the way you strap in or just apart of the process, is it possible you are stretching the skin? I find i stretch the skin there alot, i have some stretch marks in that area and it does get irritated, For me i think the irritation is a combination of the
SG stretching plus shaving there for the
Bathmate.
Hope this helps