Benefits:

• This worm increases your wisdom score to 17.
• Once per long rest, you can make a wisdom saving throw, an animal handling check, an insight check, a medicine check, a perception check, and a survival check with advantage.
• Once per long rest, you can you can use an action to cast the Zephyr Strike spell from it. You can do so one additional time per long rest, but this will cause you to have a -1 to your wisdom score until you finish a short rest and will not receive the worm's benefits till you have completed a long rest.

Combat:

This worm feeds off your adrenaline. It operates in a similar way to your parasympathetic nervous system. It keeps you calm and level headed. If you go into combat while hosting the worm, you must spend some of your energy keeping yourself calm. You will need to either:

A: Forge adding your proficiency bonus to all attack and damage rolls.

Or

B: spend an action, bonus action, or reaction to keep yourself calm until your next turn (if you wish to use your reaction, you must commit to doing do before you end your turn) (You may also chose to spend a second attack action at your DM's discretion).

Or

C: spend 1 ki point per battle

If you do not do one of the above, you will have a -1 to your wisdom score until you finish a short rest and you will not receive the worm's benefits till you have completed a long rest. (This applies if during any one round the player has not used option A, B, or C, unless the player is stunned, incapacitated, dead, etc.)
          Options A and B can be used together during the battle. I.e. one round you could use option A and another round you could use option B. 

Removal of the Worm:

This worm has a largely symbiotic relationship with its host. To remove the worm you must be targeted by a spell or other event that has the effect of removing a curse (including the Remove Curse spell). Once you have removed the worm you will have a -1 to your wisdom score until you complete a short rest or are again host to a Wisdom Worm.
Once removed, the worm immediately searches for a new host. It will pick a person at random who is within 120 feet from it. The worm has an equal chance of selecting you as its new host. An unwilling prospective host may make a DC 14 dexterity check to avoid the worm and a DC 18 check to capture the worm. The worm must be cared for once caught or it will die.

Notes: www.artstation.com/artwork/lxz5aV?album_id=72664 (Image Credit: Xabi Gaztelua Freelance Illustrator for Arcana Games LLC), simply allowing the Wisdom Worm to bite you. Once it has latched onto you, it will burrow it's way into your abdomen and feed off the hormones produced by your adrenal glands., Symbiotic