oh.
i just realised the other part to your question. yeah, it is possible that that is why you feel disgusted (and maybe a little afraid?) of penises now.

on a slightly related note...
this happened a few years ago...

i was with my friend (my f-buddy actually) and we were driving up his driveway and his neighbour came out and was talking to us through my window. i'd interacted with him a little before, and he was alright in his own special way i guess, but i thought he was a little bit sleezy). he was talking with my mate kind of across me... and we were eating these ice-block popsicle things. just before he turned to go he looked me right in the eyes and said 'the way you are sucking that i'm surprised we aren't better friends'. then he walked off. i felt horrified. repulsed. disgusted. shocked. i guess that was the point behind what he said? i don't know. my mate apologised to me and said he found it really very inappropriate - but it wasn't his fault, of course.

i could think about that incident from an adult place. took me a little while... hindered my sexual activity for a while... (his face kept occuring to me at inappropriate times and that was a bit of a killer)... hindered my ice block eating activity at times... but i was in an adult place and i could process it and i came right eventually (within a few months).

you were 12 and your parents wouldn't help you process what had happened. it must have been pretty scary. i think things like that (exhibitionism) is partly about power. about shocking the person. all kinds of feelings of shock and disbelief and fear and disgust... and when we see our parents respond similarly instead of helping us process those feelings...