Help my bf's wierd fetish

i'm 17 and my bf's 21 and we have been together for about a year
my bf wants to watch me go poo and he wants me to do it on him
i mean we enjoy rimming and things like that and i actually like when he licks me there, but i'm not too sure if i could do the full thing he is asking
but i really love him and i want to make him happy
does anybody know about this fetish and have you done it before?

Hi

i have but only once a crapped on an exs chest while he watched it did'nt do nothing for me lol,,,,,the smell alone put me off then his request got a bit to sick to stomach and he had to go so sweetheart your not alone do what you feel is comfortable to you both