If you want it quick then finding a character with higher stats and fusing and paying for the higher stat with crystals is the most straightforward option. You can minmax your start with stuff like Hatcher and a high magic stat starter to potentially get eggs hatching overnight but more practically over two days. Or get lucky in portals nabbing some decent genetics mob. Any way you skin it quickly raising stats within the first few days is going to be tricky or ask a highly specific start.
If breeding is really slow to produce eggs then that stat is sorta secondary to the problem. It effects how much Virility raises on level up. Higher max level, leveling up, larger sizes will also increase effective Virility for faster/more egg production when breeding. According to the wiki there's also a 20% multiplier for having a Male character instead of Futa. Some species are also much better at the breeding stats than others, Centaurs being pretty good for example and Lymeans being abysmal.
