Thanks for query,
Testicles are abdominal organ in initial years of life & then it becomes a pelvic organ afterwards.As you have undergone an operation to make it pelvic organ now it is not necessary to pull it down.The skin of scrotum
& dartose muscle is retract & contract with eeffect of temperature .
This is required & necessary as sperm production is done in testis so it controls the temperature to facilitate it's production.
I think you should wear loose cloth to make you comfortable while sitting or during sex.