IF YOU ON A DATE OR EATING OUT AND ''HAD TO TAKE A DUMP'', would you tell your mate?

No need ever to say why you need the restroom.

No. You simply say "Excuse me, I need to use the restroom. Be right back."
There is no need for him to know what you are actually DOING in there.

No, that's TMI. Just say, "excuse me," and go visit the public restroom. Don't say why you are going there.

why do you dream up this crap and post things like this
go to work

If one is eating then I don't think that one is going to appreciate being told that their counterpart is off to the bathroom to go for a number 2, so, no, you just excuse yourself & get on with what you must do.

not a neccessity

i would just say excuse me, i'll be right back, i need to use the restroom

Depends how long you have been dating the person. If this is the first date, HELL NO. Just go to the bathroom and try to be quick. They'll never know. If you've been dating for a few months, and you feel comfortable with this person, then it would be more acceptable to be straight up.

It's okay to use the bathroom, anytime.

Yeah I'd say "I need to take a huge ****" and she'll be all cool and like "Go have a good one".