How do I rotate the model when it has already been rotated

[tunnelman]

I want to take a model. then apply a roll and then apply a yaw

this is what I have:

model = glm::rotate(model, glm::radians(therot[k]), glm::vec3(0, 0, 1));
model = glm::rotate(model, glm::radians(inrot[k]), glm::vec3(0, 1, 0));