The breast weighed heftily on your right, the nipple greedily closing up around the man's feet as they were fully sucked in. Most of their mass shifted downwards and became a fifth tentacle, but a decent amount remained in the breast, pushing it out to a solid DD cup. The other man would have been screaming had you not covered his mouth with your third tentacle. You savor the pleasure for a moment before looking towards the other man, who returns your gaze, frightened. Smiling with teeth like a shark's, pointed and deadly, you bring him to your other nipple intent on repeating the process.
Using two tentacles you jab them inside the nipple and pull it open, oddly causing no pain to you as you introduce the man's head, the sides snapping shut over his neck. And with rhythmic motions you begin pulling him inside more, your gills flaring with every pulse, every breath. It felt just like stuffing a dick inside your pussy, just higher, and you were starting to lose yourself in a haze of heat and passion. Mouth open, teeth glistening, your tongue rolling down with a much longer length and, mostly out of your control, helping push the man in further. One of your other free tentacles ventured down and began stuffing itself into your pussy as well, adding to the pleasure. When his hips get introduced you start bucking as well, your tentacles writing underneath the water as a sixth one begins joining their ranks. Had you not been underwater everyone else in the pool would be repulsed from your exuberant moaning by the time his knees enter. This was so much better than any sex you've ever had previously. And then, just like that, his feet came in with a schlorp, and your nipple sealed shut once again, shrinking down as it distributed the mass to the new tentacle. He had been a fair bit heavier than the last, and your beautiful breasts had gone from double D's to double E's, freely floating within the water.
You licked your lips with your longer tongue, your now slitted reddish pink eyes flitting to the rest of the people in the pool. You had stopped thinking of yourself as wearing a costume a while ago. In fact, one could barely tell where the seams ended and you began. What constituted the tentacles was flesh and blood, and there was no more zipper either. You were a Cecaelia now, in body and in mind, and to be honest, you were all for it. And you still had tentacles to fill up. So, who was next?