While it may seem like a good spot to hero call, I think the fact that 5 people called your raise preflop makes it less likely that villain is bluffing. When he calls otf, the only hand combos you beat are smaller FD's and 64 (and 64 made it there otr). I think I would rather semi-bluff ott rather than make the hero call otr. Or you could always go for that weird c/r otr, but I'm not sure if villain will believe you. Would be interesting if you tried that