Farter.cs

using UnityEngine;
using System.Collections;

public class Farter : StateMonoBehaviour
{
    void Start()
    {
        SetState(Normal);
    }

    IEnumerator Normal()
    {
        while (true)
        {
            if (Input.GetKeyDown(KeyCode.F))
                SetState(Fart);
            yield return null;
        }
    }

    IEnumerator Fart()
    {
        Debug.Log("now farting!");
        // play some animation or something
        // wait a second
        yield return new WaitForSeconds(1f);
        // go back to normal state
        SetState(Normal);
    }
}