A sexual fantasy that you wouldn't mind being foisted upon the unsuspecting world.
Aliens have landed on Earth, and they are far from little green men. They are more-or-less a tangle of massive, writhing, sputtering tentacles surrounding a self-sustaining core; an appearance not dissimilar to a sea urchin. Among other lures, they secrete a gas that causes hallucinations in humans to lure them in, some have reported being beckoned by dead love ones or promises of great luxuries.
The victim is first stripped to their bare skin. Following that the victim is restrained and has tentacles inserted into their mouth and anus which proceed to give the victim a blast of muscle relaxant and anesthetic. The victim then has their genitals engulfed and pumped full of goo to both feed them and mold them into a quality vessel for its young, which in humans would be a voluptuous female large enough to carry many eggs at once to term and live afterwards to potentially do so again and again; the results resembles a particularly soft fertility goddess scaled up to the size of a professional basketball player. The transformation lasts mere hours.They will be unconscious or semi-conscious for most of their stay.
Although relatively infrequent, captures are frequent enough that both the state and private institutions to deal with rehabilitation are easily found in major cities, their main purpose is to prevent suicides and provide medical care. Although physical changes are drastic, most victims remain identical mentally to their pre-capture selves including their sexual desires. There are also many preventive measures that can be taken, from wearing special masks in known areas, oral and aerosol medications promising immunity, and educative films/literature demonstrating bait. But the creatures quickly adapt and it's a never-ending race to try and minimize captures.
pity bump for the sorry cuck
Women no longer get immediately pregnant when a man cums in them (so they also don't need contraception). Instead they can store the man's cum for around 6 months, and choose to get pregnant at any time during this period. Furthermore, a woman can store the cum of multiple men if she fucks all of them. Due to this, the child can have the genes from the cum of multiple men. Woman also have a sense that allows them to choose what genes from what cum they want in the child, meaning that they could fuck a smart but ugly man and a beautiful but dumb man and then put the smart and beautiful genes into their child.
As a result of this, women will tend to fuck multiple men before choosing to get pregnant so that their child can have the best genes. Because of this, having sex with someone else apart from your partner is socially acceptable and very common. Being able to have sex with a woman is also seen as a sign of respect from the woman, because she is willing to consider having some of your genes in her child.
For example a female boss of a company may let her best male employees fuck her so that her child will have the best traits of all of them. Another social situation that changes is weddings. At weddings, the groom and his grooms men will be invited to participate in a gang bang with the bride so she can collect cum for her child. Public sex also becomes a lot more common, because if a woman sees a man she thinks is cute, then she will try and fuck him to collect his cum.