It depends, really. If i were to date a girl who was really lovely and everything but had bigger penis than me and was better at it, it would really bring my self-confidence down. It would be even worse if she was putting that in my face (not her penis) that she had a bigger penis, getting a punch or kick from me would be the least of her worries :/.
I know this is off-top but regarding manga itself i wonder if futaba has a fully functioning vagina or she has only penis/balls/anus like any other men and only difference is that that she possess some glamourous tits and girly voice.
While domestic violence is definitely a no-no, you'd probably be in a bad relationship if your lover was comparing their body to yours negatively( like a super model telling her mate how plain they look). Alternatively its always important to remember that skills matter more in a sexual relationship than physical traits, and hopefully if she was more competent in bed than you she wouldn't be critical or undermining.
For the sake of argument and until the author states so obviously; I'm personally going to assume she has functioning organs of both sexes. As for gender, female seems to be her preference but we'd need to know if she uses female pronouns to be sure.
Her sexuality......Bisexual probably, though maybe trisexual if she likes other futas?
Edited by IlikeLolis, 18 December 2015 - 05:29 AM.