What does it mean to aim sidespin shots with “parallel english?”
People use different definitions of “parallel english,” but here is the standard and most common definition from the online glossary:
parallel english: aiming technique when using sidespin where the cue is placed parallel to the line of aim for a center-ball hit (with no sidespin) resulting in no compensation for CB deflection (e.g., for shots where swerve is expected to cancel the effects of squirt and throw, resulting in no net CB deflection, or where the amount of resulting pocket cheat is acceptable).
Some people instead interpret “parallel english” to mean: Based on experience, instinct, and/or intuition, place the cue in the desired stroking direction, with the tip already at the position needed to created the amount of sidespin desired, and with the cue already pointing in the direction necessary to compensate for squirt, swerve, and throw. In other words, don’t line up center-ball first and then use a pivoting method (like BHE, FHE, or some combination) or a swooping stroke to arrive at the necessary line of aim to use the amount of sidespin desired. This is how pretty much all pros and great players aim when using english; although, this should not be called “parallel english” unless the cue is in fact parallel to the aiming line of the CB at address.
Regardless of how you determine the necessary stroking line of the cue when applying english, even if completely intuitively, the cue must be pointed in a certain direction for given shot to send the OB into the center of the pocket. For example, with a short distance between the CB and OB and/or with a firm shot, BHE (with an appropriate bridge length) will give you a good line of aim. If you use true parallel english with a shot like this instead, it will be way off (especially for larger amounts of sidespin). An alternative to BHE is to aim intuitively and bring the cue into the necessary line of aim with no pivot, but if you don’t have the cue in the same direction created by the BHE approach, you won’t pocket the shot (unless the pocket is close and/or large and can be cheated significantly). For more info, see compensating aim when using sidespin.