Fig.: to have someone completely under control or to have someone heavily influenced by you

With the evidence we have on his wrong-doing, we really have him in our pocket

Con le prove che abbiamo sulle sue malefatte, lo abbiamo veramente in pugno

I can't understand my friend John: he's 30 years old but he's still under his mother's thumb

Non riesco a capire il mio amico John: ha 30 anni ma vive ancora sotto il totale controllo di sua madre

We can't refuse his outrageous offer and he knows it. He got us over a barrel

Non possiamo rifiutare la sua offerta scandalosa e lui lo sa bene. Insomma, ci ha in pugno

Mike is so much in love with Linda that he would do anything for her. She's got him right under her thumb

Michele è talmente innamorato di Linda che farebbe qualsiasi cosa per lei: è completamente in suo potere

The origin of this idiom is not clear. According to some theories, though, it's a falconry term. Once the falcon has landed on the handler's fist, the handler moves the leather tether under his thumb to get some control on the falcon