I agree with swimdoc. Its a compliment. I get compliments on my body and tattoos all the time and my huge balls. No offense taken. If a dude compliments you just say thank you and no need to carry on the convo. Now If its attached with a sexual innuendo then obviously thats a different convo.
If I am not taking the question too far. I have an observation. People are self conscious about their physical attributes. Am I too big, too small, too short, too tall, etc. I am biracial , and was raised equally in both black and white communities. I noticed long ago that black people often deal with those insecurities differently.
Individuals are individuals, but in general, black people make comments about things people are insecure about through humor, which acknowledges the defect but takes away the shame (I think?). White people are more likely to pretend that they dont notice a difference. There are limits, of course, but I have close friends and family members who have nicknames like shorty, fat, red, and jughead for reasons that are quite apparent when you meet them.
I might be hesitant to mention out of the blue that someone has a large or small penis or breasts, but sincere compliments should be taken as such. People have mentioned my unusual skin color often out of curiosity or admiration. I just say thank you and move on.