Venting works also males are more barrel breasted in my opinion.... The females do get a blueish hue in the top front of the dorsal.. But in my opinion the best way is venting.. male is v and female is u
Female front male rear
Male
Female
Male left female right
Female.. In this pic you can make out the Size and roundness of the female Organ.
In these two you can make out the Males sharpness in his Organ.