the expression "suck my dick!" been around for a long time. apparantely some people add to the insult by even showing their dick.
now there's a few things you can do to handle the situation. here's a few verbal responses:
"not now, cant you see im eating! maybe for dessert"
"thank you kind sir, thats a very generous offer, but as a married man i have to stay true, that would be considered cheating"
"only if you bend over first (no homo)"
or
you could turn it around on them showing YOUR dick - "howabout you suck mine, bitch!" (this doesnt work if your dick is smaller)
or
you could wipe out your dick and say "how about we have a sword fight instead? en garde!"
or you could just walk away.
so as we can see here, there's plenty of other options than fighting the guy.
Hmmmm

And this is your best replies to the following questions I asked in a serious respectable manner
And what would you have done ?
Moved away ?
Pacified him by giving him your food ?
And why should you move or give food you payed for to sum Homeless man
Acting a Pratt by making a nuisance / Exposing himself.
What would a cop of done to him for doing the same behaviour ?
I’m not so sure there was a “correct/proper” way to handle the situation
Other than the Homeless man just leaving people alone & behaving decently.
Very Clearly you don’t wish to engage in a meaningful dialogue or you’re incapable.