explanation

this story is connected to a story in "zhen" (chapter 6).
(this comment will contain spoilers so read both this oneshot and chapter 6 of zhen before you read my comment)
so there isn't any confusion, we'll call the seme flower 1, and we'll call the uke flower 2.
now. this oneshot follows flower 1's pov. we see that he is in love with flower 2, but flower 2 is in love with an insect, and wants to bear fruit for him.
every year, one (1) flower is chosen, and that flower will bear fruits. flower 1 has been chosen for a couple times before this oneshot. flower 2 wants to be chosen, like i said before, so he can bear fruits for that insect he's in love with. so, flower 2 goes to flower 1 during the winter to get advice on how to be chosen. they have sex, flower 1 doesn't admit his feelings though. he says that to bear fruits, a flower needs to be jealous.
flower 1 is jealous of the insect that flower 2 is in love with. which is why i think he was chosen for a couple of times.
after this, flower 1 "retires" and nominates flower 2 to be chosen next. flower 2 is chosen, as we see in ch 6 of zhen.
now, let's move over to what's happening in ch 6 of zhen.
we are introduced to the insect that flower 1 is in love with. he's having a flashback to a year before, when he learned that flower 2 could not bear fruit or nectar. flower 2 says that while he cannot bear fruit, he loves the insect.
the flashback is over, and we see the insect, who is with flower 1, pollinating (having sex). flower 1 tells the insect that only one flower out of all the rest bears fruit. he also asks the insect "just how many times this year have you been covered in pollen?" which indicates that this insects goes around to a lot of different flowers. the insect responds "i can't help it, you all smell so delicious, even though there's nothing inside". at this point, flower 1 tells the insect that flower 2 had become the top flower if that year. (the fact that flower 1 tells him this is important). he says that if the insect is looking for fruit, he might find some there (with flower 2).
there is another small flashback, where flower 2 tells the insect "i don't want to let you go to any other flower" (jealousy). so then, the insect heads over to flower 2. as he approaches, flower 2 tells him to not come any closer because he's covered in another flower's pollen. the insect asks if flower 2 is jealous, to which flower 2 responds "i had no idea! to become the top flower i..." at which point, the insect flies down into his flower. he's looking around, and mentions that there's a barb at the top of the flower, then asks himself how he's supposed to get out.
we then see flower 2 say "there's no exit." flower 2 then explains that if a flower becomes the top flower of the year, they close the escape hatch for insects. he says "you can never leave here again. i will use the pollen on your body for fertilization and make fruit. the most splendid flower is a deeply jealous one."
additionally, the flowers are japanese arisaema. these are sex-changing flowers, as the author stated. these flowers have a "pitfall trap". usually, it's carnivorous flowers that have this, but the arisaema use it as a method of pollination. the key points that relate to this story are the differences between the male and female plants. male japanese arisaema have a hole at the bottom of the flower so that when an insect goes into the flower, they get a bunch of pollen on them and come out of the hole at the bottom, then (hopefully) go to a female flower and pollinate. this is key, because the insect that flower 2 is in love with was stated to "be covered in pollen" often, which indicates that he goes through a lot of male flowers (perhaps all of these encounters are sexual, but we aren't really shown an explanation). in any case, this is why flower 2 was okay with meeting the insect. the insect could still leave the flower afterwards.
now, the female japanese arisaema, however, doesn't have an escape hatch for insects. it would be really hard for an insect who went down into a female arisaema to get back out, hence why flower 2 was crying. therefore, the insect most likely would die.
i hope this explained some things to you, because i think this story was wayyy too vague.