Being a Suggestion 5E spell you do suggest a course of activity (limited to a sentence or two) and even magically influence a creature that you can see within a range which can able to hear you and also understand you. So, the creature which can not be charmed are else immune to this effect.
Basically, the 5e Suggestion should be worded in such a manner like to make the course of an action sound reasonable. By asking the creature to stab itself, through itself onto the spear, immolate itself, or else do some of the other obvious harmful act ends the spell.
Anyhow, the target should make the wisdom saving throw. On a failed save, it normally purses the course of an action which you described to the best of its capability. Basically, the suggested course of an action can continue for the entire duration. Suppose, if the suggested activity can be completed within a shorter time, then the spell ends when the subject finishes what it was asked to do.
Of course, as per this dnd 5e Suggestion spell you can even specify the conditions which will trigger a special activity during the specific duration. For an example, you may suggest that a knight would give her warhorse to the first beggar who she meets. If the condition wasn’t met before the spell would expire, then the activity is not performed.
But if you or else any of your companions do damage the target, then the spell ends.
Attributes Of DnD Suggestion
|Casting Time||1 action|
|Classes||Bard, Sorcerer, Warlock, Wizard|
|Duration||Up to 8 hours|
|Material||A snake's tongue and either a bit of honeycomb or a drop of sweet oil|
|Target||A creature you can see within range that can hear and understand you|