Why is it that my panties be so moist and i don't have a discharge?

Sweating: The vaginal/vulvar/perineal area is loaded with large sweat galnds. You are wearing panties, a dress or pants and you are exercising (even if sitting). The area sweats. If you get sexually excited, you can produce secretions (not discharge) and this will wet your panties. It sounds very physiologic.

Sweat or leakage: Can be sweat or a condition called urinary incontinence.

? Post void dribble: Occurs in some women who urinate with thighs closed so some urine is trapped behind the labia, then when subject stands up & moves urine escapes. Try urinating with thighs widely apart which means pulling panties down to ankles. Other cause could be stress incontinence where a little urine is lost wuth coughing, sneezing, going downstairs etc.Could be sweat, specially if not wearing cotton panties.