What can Guerrilla UX be? Here is how Carine defines this practice:
If you are a designer, you have probably already heard something like this: “User research? Well, no we can’t do that because of the tight budget and we have to develop the feature quickly”… This is where Guerrilla UX comes in. The idea is basically to simplify user research and UX design methods to adapt them to the constraints we might encounter in our projects.
Yet Carine goes further and explains it can also be about expertise constraints, especially in small teams that don’t have the necessary resources and skills. It’s therefore very interesting to look into these techniques and make compromises according to our constraints. It’s always better to set up user research at a lower cost than not do it at all. But beware, this can’t be improvised either. With poor execution, you run the risk of basing your project on incorrect assumptions.
This podcast talks about Guerrilla UX in detail with concrete and inspiring examples. I would recommend that you listen to it if you are looking to quickly set up user research or UX design processes. For a presentation of the different techniques, take a look at Carine's conference at BlendWebMix 2017 (French audio resources).
As a UI Designer, I also use her reference book in the UX design field. A very good publication to practice and improve your UX Design knowledge.