You could try casting the third-level spell conjure animals:
You summon fey spirits that take the form of beasts and appear in unoccupied spaces that you can see within range. Choose one of the following options for what appears:
- One beast of challenge rating 2 or lower
- Two beasts of challenge rating 1 or lower
- Four beasts of challenge rating 1/2 or lower
- Eight beasts of challenge rating 1/4 or lower
Each beast is also considered fey, and it disappears when it drops to 0 hit points or when the spell ends.
The "stench kow" is a beast which has a challenge rating 1/4, so it qualifies to be summoned by this spell.
The catch is that the spell doesn't specify who decides what beasts you get, and Sage Advice tells us that the DM is allowed to decide. If your DM isn't feeling friendly, they could narrate that you get some other beasts instead of the beasts you were hoping for. (They might narrate that the beasts that show up are beasts that would be native to the area.)
So: lay out a circle of stinkweed and durian and whatever else you've got that you think would be attractive to stench kows, then cast your spell and hope for the best.
If conjure animals doesn't work, in theory you could also find a high-level cleric friend to cast the sixth-level spell planar ally. This spell normally only gives celestials, fiends, or elementals, but perhaps you could get an exception in this instance.
A third option would be to hang out with some druids at your local druid circle and ask if they'd like to trade wild shape forms with you. Even if you don't specifically get a stench kow, they've probably got some good forms which you could learn.