There are no children in Warhammer Fantasy that have been born as Vampires. It does not work. There are a few who have been sired at a very early age however.
There are fat vampires (Ulrika The Vampire: Bloodforged, if I recall correctly). They are however rare and at least the one I know, used her mass as a strange "shield".
Vampires can eat food/drink but it's tasteless/pointless, only done for a show.
Vampires can have sex, but not quite how humans do. Though there is plenty of touching as well, but it's difficult if not impossible to say how well their private bits work, if at all. Forgive me here, I can't properly quote everything here, but here are some examples (everything is vamp/vamp):
"She shivered as he kissed her, both aroused and vaguely unsettled."
"Her hands remained where they were and she lay still, tensing as Stefan’s sharp teeth dragged across her skin, then sighing and clutching him tight as they pierced her flesh with a delicious shock of pain and found her vein. She closed her eyes as he began to draw blood from her with gentle pressure. This was a different sort of pleasure than taking blood. That was the pleasure of hunger sated and strength returned. This was the pleasure of control lost and the drifting, sleepy rapture of tension released. The dark memories of Krieger faded away, to be eclipsed by rosy dreams of flying, of gliding with Stefan like dragons in a sky of blood. He was leading her, drawing her on in his wake, and she was happy to follow, to let him choose the path, to give herself up to his will and let him do with her as he pleased. If he wished to drink his fill and let her die, so be it. She would die in bliss, floating towards his warm red sun until it consumed her in its molten core. She groaned in dismay when he raised his head and the kiss ended. It felt as if a cord between them had been cut, and she was suddenly cold and alone. She cupped the back of his neck and pulled him back down again, but he resisted."
And the juicy part:
"She pulled his mouth to hers and bit his lips and tongue, drawing blood and sucking greedily. He bit back. They clawed at one another, tearing away each other’s clothes and writhing against one another. From the few things Gabriella had told Ulrika about love between vampires, she had thought it would be nothing more than the exchange of blood, but now she discovered that was not the truth. They were animals, after all, beasts, who must learn to control their savage natures or they would tear their victims limb from limb. Their love was just as animal as their feeding – pain and pleasure in equal measure, biting and kissing, clawing and caressing, wounds that healed as soon as they were made, and bare skin made slippery with blood and tongues. She had never experienced anything like it before. Not during the rough galloping of horse soldiers, nor the fights with Felix that became romps and then fights again, nor the shameful, sensual surrender to Krieger. This was wilder than any of those, the pleasure stronger and more enduring, the play more give and take. There was a danger to it that only made it more exhilarating. Either of them could take too much and kill the other. It felt as if they were rolling on the edge of a precipice, daring each other to fall to their deaths."
There have been quite a few situations in many books were a vampire felt physical/sexual attraction towards a mortal (or another vampire). Though like said before, if they do the kinky stuff like humans? Who knows! I am fairly sure BL will never bother to think on it too much.
