An attachment for a writing instrument, comprising a support member comprising a distal end (D) and a proximal end (P), wherein an attachment axis (A) is defined between the distal end and the proximal end, wherein the support member is configured to be attached to a writing instrument, an inertial measurement unit, wherein the inertial measurement unit is configured to measure a movement of the attachment axis (A) between a first and a second position of the attachment axis, a momentum wheel assembly, wherein the momentum wheel assembly comprises a first rotatable member coupled to a first motor, wherein the first motor is configured to apply a variable torque to the first rotatable member, and a control unit configured to actuate the first motor based on the movement of the attachment axis measured by the inertial measurement unit.