Order of variable for simplification

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Let's say I have two variables x, q. When I use simplify_full(), how do I make sure the final expression is ordered as monomial of X instead of q? For example, let f=q^2+x+1, g=qx+1. Somehow if I use simplify_full() to simplify fg, then the monomial is of the following form (expression in terms of x)q^3+(expression in terms of x)q^2...

But actually I regard x as the variable, q as power of prime number. So I wish to order the expression like: (expression in terms of q)X^2+(expression in terms of q)X+(expression in terms of q)

Thanks!