You press the strings with your fretting hand. The thing is, that hand works as a "movable nut" in your bass. You fret the notes as in regular playing and your right hand should reflect left hand's movements.
WHAT!?!
An someone please explain what is going on? Are you refering to regular harmonics?
__________________ "Yet a time is coming and now has come when the true worshipers will worship the Father in spirit and truth, for they are the kind of worshipers the Father seeks." John 4:23
I made a thread about this about 2 weeks ago, so it shouldn't be too far back. Anyway I'll try to explain the technique. First make a thumb's up position with your picking hand's thumb. then turn it upside down so your thumb is point towards the floor. Then rest the joint of your thumb (crease where the thumb bends) LIGHTLY on the string in front of your hand. then pick with your pointer finger behind the string and you should getr a harmonic sound
Put the thumb of your right hand on the harmonic over the 12th fret.
Use the index finger on your right hand to pluck the string, behind the thumb that is "stopping" the harmonic.
When you are used to this, try fretting a note with your left hand, and doing the octave harmonic (12 frets higher than the note you are fretting) of that note.
When you really start getting into it, figure out where the harmonics other than the octave are and start ripping into it with gusto! I've found that it's easier to do pinch harmonics on the thicker (lower pitched) strings.