how to make an sliding sound effect?

I have my character slide along a wall kind of like in megaman X and I want it to make an sliding sound effect, the problem is that I can't make it sound right, this is the code I'm using:

1. publicAudioClip resbaladizo;
2. voidAwake()
3. {
4. audio.clip = resbaladizo;
5. }
6. voidOnCollisionStay(Collision lacolision){
7. if(lacolision.gameObject.tag =="Player"&&(lacolision.rigidbody.velocity.y<-5|| lacolision.rigidbody.velocity.y>5))
8. {
9. audio.Play();
10. }}

As expected, the sound clip sounds every frame the character is in the wall so the one-second sliding sound effect sounds terrible as it is being re-played every frame. Anybody has a good solution for this? Thanks in advance!