Select EXTRA OPS mission: Date with Paz .
You can wear any uniform in this mission. We just wanted to try the tuxedo and we thought it's more appropriate. Leave all weapons and bring two items: LOVE BOX and CAMERA!
The point of this mission is to win Paz's affinity. Edit your co-ops comm with the phrases you think will please her. Example:
Once in the mission, approach Paz. Say the nice phrases that you think she'll like from the co-ops communication. By the way, pressing CQC will make Snake grab Paz's chest. You can try it to see for yourself but then you'll have to restart mission because it affects the affinity.
If you think you've talked to Paz long enough basing on her response and gestures, you may start taking her pictures. Again say a few nice things. After that you should be good to put out the love box.