Wrap (one's) head around (something) American phrase informal
The noun "mind" can substitute for the noun "head".
The verb "get" can substitute for the verb "wrap".
If someone "wraps his/her head around something", he/she tries to understand or accepts something that is difficult, strange, or out of ordinary.
She found it hard to wrap her head around complex issues related to astronomy or geology.
I can't wrap my head around this math question.
After her recent breakup, she couldn't wrap her head around true love.
The verb "wrap" should be conjugated according to its tense.
The expression "wrap one’s head around something" seems to have appeared in the 1970s and maybe primarily an American phrase.
To make love or have sex with someone
They just jumped each other’s bones after one date.