She bucked up at him and another inch of hard daddy-cock impaled her. There was a little pain involved and she thought that perhaps that was her limit. She looked between their bodies and saw that there was still another couple of inches of his incredible organ that she had not yet been able to take. She knew, however, that she had a prodigious volume of man-meat inside her. Her mind wandered back to math class when they learned to find the volume of a cylinder. What a cylinder! She put her hand on her father's chest, signaling him to stop. He was deep inside her and it felt wonderful....