One of my old favorite jokes is "What is gray and comes in quarts? An elephant." But is it biologically accurate? FACT-CHECK: No. For example, Kiso et al. (2011) obtained ejaculate volumes from African and Asian elephants on the order of 50 mL, well under a cup.
In search of the true bukkake champion of the animal kingdom, let's consider the blue whale. Simmons and Jones (2007) state with no citation that a blue whale ejaculates 4 gallons. But I think 4 gallons may be exaggerated. Some back-of-the-envelope calculations suggest that humans emit .02 mL of semen per kg of average male body weight, and African elephants .01, but blue whales .15. A ratio of .02 for blue whales would give 2 L instead. If anything, I would expect absolute seminal volume to be about equal between species, even ones of vastly different size. Syngamy only requires one sperm cell, and bigger animals are bigger because they're made out of more cells, not because they have bigger cells.
Is that more than you wanted to know about this topic? You're whale-cum.
Kiso, W. K., Brown, J. L., Siewerdt, F., Schmitt, D. L., Olson, D., Crichton, E. G., & Pukazhenthi, B. S. (2011). Liquid semen storage in elephants (Elephas maximus and Loxodonta africana): Species differences and storage optimization. Journal of Andrology, 32(4), 420–431.
Simmons, M. N., & Jones, J. S. (2007). Male genital morphology and function: An evolutionary perspective. Journal of Urology, 177(5), 1625–1631.