Goes round to block up drip internally (6)

'goes round' is the definition.
Although both the answer and definition are verbs in their -s form, I cannot see how they can define each other.

'block up drip internally' is the wordplay.
'block' becomes 'stop' ('stop' can be a synonym of 'block'**).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'drip' becomes 'iv' (intravenous drip).
'internally' means one lot of letters goes inside another.
'stop' written backwards gives 'pots'.
'pots' going around 'iv' is 'PIVOTS'.

'to' is the link.

Can you help me to learn more?