Participation in sensemaking discourse is widely seen as important to students' learning in physics classes. Many physics curricula and pedagogical strategies use collaborative small group activities to create opportunities for students to engage in authentic collaborative sensemaking discourse, but we also know collaborative small groups sometimes function inequitably. Access to discourse in them is co-constructed by group members and impacted by both the histories of individual members and the cultural attitudes and expectations they bring. As a result, some students can be marginalized and excluded from fair access to valuable participation in discourse. This study focuses on one student in a previously studied small group known to frequently function inequitably. The focus student, "Jessica", was an infrequent participant and arguably a low-influence member of the group. Because she was usually denied fair access to participation in the on-task sensemaking discourse, Jessica is a type of student our research community needs to focus on as we work to better understand the dynamics of collaborative small groups. By analyzing video data of this group, this study aimed to understand how Jessica negotiated her, albeit infrequent, episodes of participation in on-task discussion. Using positioning theory as the primary analytic framework, the analysis illustrates how Jessica negotiated on-task participation opportunities by establishing access to the conversational floor and/or positioning herself with authority in off-task discourse and leveraging that to negotiate access to the group's on-task discourse.