Many bulls insist on spending the night (aka a sleepover) when they
find out the wife is ovulating. It gives them ample opportunity to get up
inside her 3 or 4 time. As well as their seed having all night to find her egg
and plant itself in her belly. Often, there's so much cum, the fallopian tubes
are packed full, waiting to pounce on an unsuspecting egg as it leaves her ovary.
By morning, the "damage is done". Her telling me to "suck out the seed" is really
just for show. It's just too late. Nothing a cuckold can do.