Some folks of the unaltered female phenotype can pee standing by angling and sort of tactically spreading everything apart with their fingers but it takes practice. Generally they can’t aim well enough to do it pants on. Testosterone will cause a lengthening of the clitoris in some trans guys making it easier but it’s not universal that pre op trans guys put in the work for this skill and one of the main advantages of Phalloplasy is gaining the function to easily piss in a stall.