Vibrational locking is the process of tapping into the frequency of your present life experience to align with it to such a degree that you continually attract more experiences that match and thus lock yourself into the vibrational frequency of that particular experience.
This can also be done through thought too. The process of thinking about your desires as if they are a reality for you right now will allow for you to continually get closer to the feeling of your desire's fulfillment and once you find that particular feeling, you can then lock onto it by continuing to think and focus in a way that locks you into the feeling of your desire presently being fulfilled.
This process essentially brings the fulfillment of your desires into the perceived present moment and if you use it, you will continually perceive and feel as if your desires have been fulfilled thereby locking your personal vibrational frequency at the frequency of your desires.
Everything that is considered to be inevitable, events that are definitely going to happen, is vibrational locking in progress. You can thus also lock onto the frequency of your desires by viewing them as an event that is inevitably going to happen. Along with viewing the fulfillment of your desires as being inevitable, you can also view them as if they have already happened to thus make them equally as inevitable.