well if you wanna be discreet about something(well anything really) doing it online is not smart and not very Discreet.
Doing things over the phone is even worse.
The best way to be discreet is to meet whomever your wanting to do whatever with during a lunchbreak or plan way ahead.
Being discreet at least to me means your doing something you are unsure of or you know is wrong or maybe trying to hide from loved ones.
Before doing something like that especially if in a relationship marrige etc. make sure your single otherwise it's called cheating/Adultery etc. and you really don't want that on your conscience.
but I will be honest on the subject of being Bi-sexual.
I know so many folks who are it's insane why be discreet your better off just being straightforward about who you are that trying to hide who you are, just be you.