How to add session tags with lambda execution role

Is there a way that we can pass session tags when lambda assumes its execution role behind the scenes for us? My requirement is that I'm signing IAM authenticated API gateway request inside my lambda function to call my another service hosted in API gateway. The problem is that I need to assume another role because I need session tags with the credentials I sign the request and the reasons for that is I'm using principal tags inside my IAM policy to further secure the access to invoke the API.