Volume 24 of the Mahou Sensei Negima manga comes accompanied with an OAD (OAV), which is to say the publishers have devised a crafty way of making fans of either version pay for both.
Whatever the case, both versions are packed full of ecchi content, with plenty of exposed breasts and an onsen special, though things stop just short of nipple exposure, as you might expect…
Basically, everything is shown short of nipples.
And the manga? It has tentacles:
Via Earl Box.