Goku knows better…
The standard is to use the 3 point contact method.
- Smile and maintain eye contact
- Place your off hand on their shoulder, or forearm.
- With other hand, calmly and gently feel for a penis.
Generally you are allowed 2 to 3 seconds of firm, static contact. It is considered VERY rude to try to get a feel for size or girth, so avoid any pinching, groping or rubbing.
Lawsuit ready to happen
Unless your Crocodile Dundee …
But seriously, in most states its considered sexual harassment or sexual assault
Also there is this
The 3 point contact method seems pretty legit! That being said, why dont you just ask her friend? The partner. Because if she does the things you discussed shes bound to know and you could probably find out in relative confidence. And depending on what you’re looking for might even be a good intro.
Ask to see her karyotype
Ask at @raz0r to get serviced by her first and afterwards you guys can measure the circumference of his butthole.
“Would you prefer to talk about sports or feelings?”
“New-Half” aka Transexual
:tup:
Just do him/her raw and see if you end up paying child support.
hard core moral manipulation vid 
Act as though you are about to kick her in the nuts. If she recoils and throws up the classical male “dick guard” defense with either movement of the leg or both hands coming down to provide a shield, she is reacting to a natural instinct that used to be present in fear that she about to get kicked in the dick. If she does not respond as such, go home and feel bad because you just kicked a girl in vajra. No pussy for you tonight.
Source: I’m a doctor and I took half a psychology class on the internet. I swear.
Say that you’ve had multiple bad experiences before with dominatrixes (just bullshit a believable story) and pop the question when it seems like she/he understands.
I would simply ask them “Do you wear underwares with dick holes?” But that aint non of my business.
Reach for the goods, if you get punched she a guy, if you get slapped she’s a girl, if she lets you touch she’s a professional…
checking for a dick might not be sufficient because if he/she doesn’t have one, he/she might have gotten it removed. And having a dick hole in her underwear/outfit could simply mean that she likes to strap on dildos and screw other girls or give guys anal.
O.o
I should have also mentioned that this person is a pro dominatrix and fetishist. So most of what these posters have suggested would make it prostitution and be off the table, anyways.