Need to identify pop song late 70's

[Hijitus]

Here is another late 70's dance song I use to listen in Argentina FM stations... sang by a woman, the chorus said "Don't hold back, if it feels good... don't hold back, if it feeeels good..."
Thanks you in advance for your help.

[Mumbles]

This might be male&female

Chanson - Don't Hold Back
http://youtube.com/watch?v=GSrlJvQQF1g

[Hijitus]

Mumbles, i am speechless! How do you know so much!!??? Just incredible!
Thanks again.