There are several synonyms for the phrase "jamming them in." One option is "stuffing," which implies forceful, clumsy placement. Alternatively, "cramming" connotes squeezing or packing tightly. Another synonym is "wedging," which suggests insertion into a tight space or crevice. "Squeezing in" also conveys a similar meaning, with the added implication of fitting into a small area. Finally, "shoving" could be used to describe forcefully pushing something into a space, which is a similar concept to jamming. All of these synonyms suggest a forceful and possibly uncomfortable means of getting something into a tight or limited space.