Iíve been with two guys who had a micropenis, one who told me beforehand and the other who didnít. I donít think thereís a moral obligation, but I do feel itís better knowing what to expect sexually in general, before getting to the moment (this goes both ways).
One guy joked about his size, etc and did it in a way where heíd slip in a more serious comment to where I knew to expect a significantly below average penis. He was really cool and we had good chemistry, so I was down to discuss our sexual interests and needs, and it was really fun regardless, as we shared a lot of kinks.
The second person didnít tell me, so I had different expectations going in. I donít know if he didnít tell me on purpose, but we didnít really talk about what we were into/wanted (there was also a lot of alcohol involved in this one), so I was surprised. We had a good time, but it threw me off because it does change what we were doing (my favorite positions wouldnít really work), so we had to pause and have a quick discussion. I also wasnít sure the condoms I had would fit, but thankfully he had some too.
Regardless, I donít think thereís a ďmoralĒ obligation to share that information, but I think thereís a practical reason to, and if size a dealbreaker to your partner, itís better to know sooner rather than later.
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