@Higher,
You definitely can.
An easy way to start is to practice just sticking to your guns nonverbally. e.g., girl tests you on something and you just give her
the bored look or
skeptical look.
Next level up is calling girls out playfully on things. e.g., the bikini girl giving you pecks from the first report you linked: "What am I, your grandma?"
The love language girl in the other one, you just need to be able to come up with some sort of ridiculous alternate love language. "You've got me all wrong, baby. My love language is people watching together and making fun of all the idiots we see. There's nothing that brings two people closer."
Next level of assertiveness up from there (though it may not be the best call for every girl/situation; for some a look is better, for others a clever line) is just holding eye contact, smiling mischievously, and insisting or denying her. e.g., kiss girl:
HER: [peck on the lips]
YOU: [strong eye contact, mischievous smile] You can do better than that. [keep holding eye contact until she looks down / blushes / kisses again]
HER: [kisses better/deeper]
YOU: There you go. [approve of her for complying]
But stick with just using a look to start as you get your backbone stiffened for these types of interactions.
It's just another type of anxiety, a "what will happen if I act too bold?" anxiety, in the same vein as approach anxiety.
Another tip, if you can find some: get some highly assertive friends and perhaps a highly assertive girlfriend or two and spend time around them observing how they do what they do. You will also probably notice they are very good at getting their ways, and that most people bend right too them. The power of being assertive...
Chase
