As well as “Riffs” and “Safe Notes” there’s also “Trills”.

Trills are 2 notes next to each other played one after the other very fast.
There are two main trills, the first is the lower trill which uses suck 3 and suck 4.
Start by sucking on hole 3 then, whilst still sucking, slide to hole 4, then slide back to 3, back to 4, back to 3 and so on.

Listen to this example see what a trill on suck holes 3 and 4 sounds like

I find it easier to wobble my head rather than my hands, but it’s whatever feels easier to you.
The other trill is the higher trill which uses suck hole 4 and suck hole 5.

Trill with suck holes 4 and 5 should sound like this

Like “Riffs” and “Safe Notes” trills can be played anywhere and at any speed, fast or slow.