If you are going to do it, i personally would just ask your regular M/L if she was cool with trying it out, and make shore the one you use is brand new and you open the packet in front of her for hygiene reasons,
now for fucking i would use a thinner tighter fit one so you can get deeper penetration and a solid blood hold in your shaft
but for a BJ and Hj get one with a ball separator so she can suck on your balls while stroking your shaft.
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