Do not be sexually intimate with your mother’s sister
“Do not uncover the nakedness of your mother’s sister” Vayikra 18:12
This applies to either a sister of the father or the mother from either the same father or the same mother, even from immoral relations.
Nevertheless, she is a sister to either the father or the mother.
The punishment for either of these 2 sexual relations, if wilfully is spiritual severance, even with witnesses and a prior warning.
If done unwittingly a sin offering is required.
This applies in all place and at all times.