i have the same problem. i iam starting to realize how slowly. #1...if iam with my woman and i get realy extremely ecited,make love to her and dont cum,then after a day or to a got the swolen nut.
#2 when i beat my monkey,i shoulden tighthen up. because mostley after ejaculating i get that damn swollen nut,so i gotta just relax.
#3 if iam working ,then i make some kinda ball busting move also gets me a swollen testical after 7 hours.
those where the ways how i figuured out the problem..
and what helps is when i feel that nut beging=ing to swell up, i try to do the splits and just stay in that position for a minut or to, then keep reaping that for bout 5 times, it helps and loosen up that zak.
man i should be a dokter..

peace out and watch ya nuts!!