This is from a ton of people I've studied but the best explanation was from Rusty Cooley's videos. A 'five' in this case would be 19 17 15 17 19 or 15 17 19 17 15 and a seven would be 19 17 15 17 19 17 15 or 15 17 19 17 15 17 19. In the last lick I posted you can see the first set of notes, on the E string, is a seven of this kind (but down a whole step, in A minor) and the second set, on the B string, is a group of five in this manner. Rusty uses them independently and in five or seven notes per beat, I'll use them like that sometimes but more often incorporate them into other rhythmic groups - instead of playing just sevens and fives, I'll mix them and match them into a sixteenth-note measure like the one above, use them as part of a triplet or sextuplet run, something like that. This is just giving other prime numbers the same chance we've all given twos and threes, rather than just doing sequences in two, three, four, or six note bits this practice of fives and sevens adds on groups of... five and seven, ta-da!, so you won't sound as robotic.
Long story short, if you have notes A B and C, fives would be ABCBA or CBABC and sevens would be ABCBABC or CBABCBA (the second ones are just upside down), use unusual note groupings and rhythmic sequences (Loomis' solo on The Final Product - the pedal tone diminished bit - uses a six-note sequence grouped into four-note spacing, called a hemiola), and however you want to throw these things into one piece is your call (it's really not that complicated). The clip shows fives and sevens incorporated into a pair of runs, using those groups but still in sixteenth-note time, and how much more interesting and tonal they can sound than the typical 1234-2345-3456 bit. You can cross strings, you can do them up and down, sideways, backwards, with your teeth, whatever, it's just using a different note grouping.
Jeff