The centring diphthongs glide towards the vowel /q/ which is a central vowel.
Iqthe starting point is a little closer than /I/ (but not too close) and the glide moves in the direction of the central /q/. The lips have a slight movement from spread to open.
eqbegins with the vowel /e/ (in the open-mid front position) and moves in the direction of the more open variety of /q/. Attention should be paid to the open-mid articulation of the first element.
Vqhas a starting point slightly closer than /V/. The lips are very slightly rounded at the beginning of the glide, becoming neutral as the glide progresses. It is not used as much as others – many English speakers use /L/ instead of this diphthong in the majority of words that traditionally have this diphthong (e.g. sure - /SL/).